“knowledge life” for 2001 cattlemen’s day · bull selection decisions, including growth and...

Report of Progress 873Kansas State University

Agricultural Experiment Station andCooperative Extension Service

CATTLEMEN’S DAY2001

“KnowledgeforLife”

This publication from the Kansas State University Agricultural Experiment Station and Cooperative Extension Service has been archived. Current information is available from http://www.ksre.ksu.edu.

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Cattlemen’s Day 2001

TABLE OF CONTENTS

REPRODUCTION, BREEDING AND GENETICSPage

Genetic Relationships among Breeding Soundness Traits in Yearling Bulls . . . . . . . . . . . . . . . . . . . 1

Carcass Merit Project: Development of EPDs and Genetic Marker Validation . . . . . . . . . . . . . . . . . 4

Carcass Merit Traits: Development of EPDs for Warner-Bratzler Shear Forceand DNA Marker Validation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 7

Ovulation Synchronization with Progestins Prior to a Cosynch Protocol in Beef Cows . . . . . . . . . . . 9

Resynchronization of Estrus with Progesterone and Estrogen in Previously Inseminated Beef Cows . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 12

Timed-Insemination of Beef Heifers Using Cosynch with or without MGA . . . . . . . . . . . . . . . . . . 15

Short-Term Feeding of MGA to Postpartum Cows Prior to the Breeding Season . . . . . . . . . . . . . . 17

MANAGEMENT

Factors Affecting Beef Demand . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 20

Motivation Factors for Beef Processor-Producer Linkages . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 23

Evaluation of Ralgro® on Pasture and Subsequent Feedlot Performance andCarcass Merit of Mexican Crossbred Steers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 26

Effects of Vaccinating Beef Dams Precalving and Calves Preweaning witha Pasteurella haemolytica Vaccine . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 29

RANGE AND GRAZING NUTRITION

Evaluation of Southwestern Kansas Native Grasses . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 31

A Survey of Phytoestrogenic Activity in Kansas Flint Hills Pastures . . . . . . . . . . . . . . . . . . . . . . . 34

Influence of Low-Level Fall Supplementation with a Self-Fed, High-ProteinSupplement and Level of Winter Supplementation on Performance ofBeef Cows Grazing Tallgrass-Prairie Range . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 37

MEAT SCIENCE AND FOOD SAFETY

Escherichia coli O157:H7 Risk Assessment for Production and Cooking ofRestructured Beef Steaks . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 42

Temperature Accuracy of an Electric Belt Grill, a Forced-Air ConvectionOven, and an Electric Broiler . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 45

Tenderness and Cooking Characteristics of Beef Cooked by Electric Belt Grill,Forced-Air Convection Oven, or Electric Broiler . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 47

Heat Penetration Patterns of Outside Round, Loin Strip and Eye Round MusclesCooked by Electric Broiler, Electric Belt Grill, or Forced-Air Convection Oven . . . . . . . . . 52

The Effects of Quality Grade, Postmortem Aging, and Blade Tenderization onWarner-Bratzler Shear Force and Cookery Traits of Biceps Femoris Steaks . . . . . . . . . . . 55


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Influences of Aging on Tenderness and Color of Beef Steaks . . . . . . . . . . . . . . . . . . . . . . . . . . . 59

Improving Color Stability of Beef Top Round . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 61

Effects of Vascular Infusion with a Solution of Sugars, Sodium Chloride, andPhosphates Plus Vitamins C, E, or C+E on Display Color . . . . . . . . . . . . . . . . . . . . . . . . 64

Relationships Among Beef Carcass Quality and Cutability Indicators . . . . . . . . . . . . . . . . . . . . . . 67

Interrelationships Among Carcass Characteristics of Feedlot Steers and HeifersSelected for Competition . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 70

GROWING AND FINISHING NUTRITION

Response of Holstein Steers Fed a Soybean Hull-Based Diet to Amino AcidSupplementation When the Methionine Requirement Was Met . . . . . . . . . . . . . . . . . . . . . 74

Branched-Chain Amino Acids for Growing Cattle Limit-Fed Diets Based onSoybean Hulls . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 77

Effects of Wet Corn Gluten Feed and Intake Level on Diet Digestibility andRumen Passage Rate in Steers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 80

Performance of Beef Heifers Limit-Fed Growing Diets Containing Alfalfa Hayand Wet Corn Gluten Feed . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 83

Soybean Hulls and Alfalfa for Limit-Fed Cattle . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 86

Rumensin®-Tylan® Combinations in Limit-Fed Growing Diets: Effects onGrowing and Finishing Performance and Carcass Characteristics . . . . . . . . . . . . . . . . . . 88

Effect of Cooked Molasses Tubs on Performance and Health of NewlyReceived Stocker Calves . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 91

Using a Mixture of Cottonseed Hulls and Cottonseed Meal to Replace AlfalfaHay in Diets for Stressed Feeder Calves . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 95

Alfalfa Hay and Wet Corn Feed Levels in Steam-Flaked Corn Finishing Diets . . . . . . . . . . . . . . . . 98

Addition of Urea to Finishing Cattle Diets Containing Steam-Flaked Cornand Wet Corn Gluten Feed . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 101

Combinations of Wet Corn Gluten Feed and Steam-Flaked Corn in Finishing Cattle Diets:Effects on Acid-Resistant E. coli and Coliforms, VFA and Profiles and pH . . . . . . . . . . . 103

INDEX OF KEY WORDS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 107BIOLOGICAL VARIABILITY AND STATISTICAL EVALUATION OF DATA . . . 108WEATHER DATA, 1999-2000 . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 108, 109ACKNOWLEGEMENTS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 110THE LIVESTOCK AND MEAT INDUSTRY COUNCIL, INC . . . . . . . . . . . . . . . . . . 111

Contribution No. 01-318-S from the Kansas Agricultural Experiment Station.

Contents of this publication may be freely reproduced for educational purposes. All other rightsreserved. In each case, give credit to the author(s), name of work, Kansas State University, and thedate the work was published.


1College of Veterinary Medicine.

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GENETIC RELATIONSHIPS AMONG BREEDINGSOUNDNESS TRAITS IN YEARLING BULLS

R. A. Christmas, D. W. Moser, M. F. Spire 1,J. M. Sargeant 1, and S. K. Tucker 1

Summary

Breeding soundness examination data onover 1,200 yearling Angus bulls were ana-lyzed to determine heritability of and geneticrelationships among breeding soundnesstraits. Breeding soundness exam procedureswere consistent with those currently recom-mended by the Society of Theriogenology.Presence of seminal white blood cells (anindicator of seminal vesiculitis), penile wartsand persistent frenulums were noted andrecorded. Data were adjusted for age atmeasurement and contemporary group ef-fects. Heritability was high for scrotal cir-cumference, moderate for percentage ofabnormalities, low for sperm motility, andnear zero for semen white blood cells, persis-tent frenulum, and penile warts. Geneticcorrelations between scrotal circumferenceand both sperm motility and abnormalitieswere favorable, indicating that selection forincreased scrotal circumference should resultin higher fertility.

(Key Words: Bulls, Breeding SoundnessExam, Heritability, Genetic Correlation,Scrotal Circumference.)

Introduction

Most beef producers use yearling bulls asat least part of their bull battery. Manyfactors may influence a cow-calf producer’sbull selection decisions, including growthand performance, carcass traits, and fertility.Of all these factors, fertility is the mosteconomically important. For a bull to beconsidered fertile, he must be able to copu-

late normally and have semen of adequatequality. Currently, the breeding soundnessexamination (BSE) is the best predictor offertility in beef bulls. The most commondefects in the BSE of yearling beef bulls areinadequate semen quality, persistent penilefrenulum, and penile warts.

We conducted this study to estimate theheritabilities of scrotal circumference, spermmotility, semen abnormalities, and commondefects of the penis. Additionally, we deter-mined estimates of the genetic correlation ofthese components with scrotal circumfer-ence.

Experimental Procedures

A BSE was performed on 1,282 regis-tered Angus bulls developed at three privateproducers in the Kansas Flint Hills, or at theK-State Purebred Beef Unit between 1994and 2000. Scrotal measurements were re-corded to the nearest 0.5 cm. Semen wascollected via electroejaculation and analyzedfor motility, morphology, and the presenceof white blood cells. Birth dates and com-plete five-generation pedigrees for all bullswere obtained from the American AngusAssociation, St. Joseph, MO. Average ageat examination was 383 days, with a range of288 to 455 days. Bulls outside this age rangewere excluded from analysis. Data in thisstudy were from initial examinations; no datafrom rechecks were included. Averages forthe analyzed traits are shown in Table 1.

Semen abnormalities were classified asprimary or secondary, as described by the


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Society for Theriogenology, and recorded asa percentage of the total sperm counted.Primary and secondary abnormalities wereadded to get percent total abnormalities. Ifmotility was <30% or total abnormalitieswere >30% the bull was collected at leasttwo more times on the day of examination.The results from the best sample (highestmotility and lowest number of total abnor-malities) were recorded. All slides wereevaluated for the presence of white bloodcells, an indicator of seminal vesiculitis. Thepresence of persistent penile frenulum orpenile warts was recorded.

The statistical model used adjusted mea-surements for age in days at the time ofevaluation and contemporary group effects.Contemporary groups defined the bull'sorigination from a common herd and man-agement system in the same year.Heritability estimates were obtained fromsingle trait analyses. Genetic correlationswere determined by pair-wise analyses ofeach trait with scrotal circumference. Aderivative-free REML algorithm was used toestimate variance components for estimatesof heritabilities and genetic correlations,similar to procedures used in most breeds’national cattle evaluation programs for othertraits.

Results and Discussion

Estimates of heritabilities and geneticcorrelations for the analyzed traits are shownin Table 2. As expected, scrotal circumfer-ence was highly heritable (0.56), and caneasily be improved through selection. Pri-mary, secondary, and total abnormalitieswere moderately heritable, ranging from 0.26to 0.35. Heritability of sperm motility waslow (0.07), and presence of white bloodcells, persistent frenulum, and penile wartswere found to have little or no genetic cause,perhaps because their incidence in this studywas very low.

Genetic correlations between scrotalcircumference and semen quality were mod-erate and in a favorable direction. Increasedscrotal circumference was associated withincreased motility (0.56), and decreasedprimary (-0.25), secondary (-0.40), and total(-0.32) abnormalities. The genetic correla-tion between scrotal circumference andpresence of white blood cells was low (-.09)and in a favorable direction, indicatingslightly lower incidence of seminalvesiculitis in large scrotal circumferencebulls.

Table 1. Averages, Standard Deviations (SD), and Ranges for Breeding SoundnessComponents and Common Reproductive Abnormalities in Yearling AngusBulls

Trait Average SD Minimum MaximumScrotal Circumference, cm 35.00 2.57 21.00 43.00% Motile Sperm 44.36 12.34 0.00 85.00% Primary Abnormalities 13.76 16.82 2.00 100.00% Secondary Abnormalities 12.16 10.26 0.00 90.00% Total Abnormalities 25.92 19.87 6.00 100.00Percent with: Seminal White Blood Cells 5% Persistent Penile Frenulum 1% Penile Warts 3%


Table 2. Heritabilites and Genetic Correlations for Breeding Soundness Exam Traits- of Yearling Angus Bulls

Genetic Correlation withTrait Heritability Scrotal CircumferenceScrotal Circumference, cm 0.56% Motile Sperm 0.07 0.56% Primary Abnormalities% Secondary Abnormalities% Total AbnomalitiesSeminal White Blood Cells

0.35 -0.250.26 -0.40

0.29 -0.32

0.02 -0.09Persistent Penile Frenulum 0.00Penile Warts 0.00

This photo taken through a microscope, live sperm cells with healthy membranes haverejected the Eosin/Nigrosin stain and dead sperm with damaged membranes accept it.photo courtesy of Dr. Peter Chenoweth, Department of Clinical Sciences, College of

rinaryVeterinary Medicine.

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1Professor of animal breeding , Cornell University.2R. D. Green, formerly Colorado State University.3Genomics FX.4Celera AgGen.5Agricultural economist, Colorado State University.6Molecular geneticist, Texas A & M University.7Associate Director for Research & Technical Services, National Cattlemen’s Beef Association.

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CARCASS MERIT PROJECT: DEVELOPMENT OFEPDS AND GENETIC MARKER VALIDATION

M. E. Dikeman, E. J. Pollak 1, R. D. Green 2,J. Taylor 3, S. Davis3, T. Holm4, S. Koontz5,

C. Gill 6, D. Moser, and E. A. Westcott 7

Summary

Carcass and Warner-Bratzler shear forcedata on strip loin steaks have been obtainedon over 4,200 cattle from contemporaryprogeny groups from the most widely usedsires in 15 beef cattle breed associations (16breeds). Trained sensory panel evaluationshave been conducted on over 1,500 strip loinsteaks from a sample of contemporaryprogeny groups from sires included in theQTL (quantitative trait loci) validationcomponent of the project. One breed associa-tion has published Warner-Bratzler shearforce Expected Progeny Differences (EPDs)for 57 sires of two breeds. DNA analysesand screening have been completed for 11QTL on eight sires from several breeds.EPDs for carcass traits, Warner-Bratzlershear force, and sensory panel traits may becompleted for several breeds within the year2001. Information from this project shouldallow seedstock producers to improve car-cass traits, tenderness, and other palatabilitytraits through classical genetic selection orthrough DNA marker-assisted selection.

Introduction

Consumers eat beef primarily for itsgreat flavor, but there have been complaintsabout its palatability associated with unac-ceptable tenderness. The National Beef

Tenderness Study published in 1987 foundthat, except for the tenderloin, tendernessvaries considerably, and significant propor-tions of nearly all beef cuts were unaccept-able in tenderness. Tenderness is generallymeasured on the longissimus (loin-eye)muscle because it has the most total value,and is almost always cooked by dry heat. Itis expected by consumers to be tender, juicy,and flavorful. Recent market studies haveshown that consumers are willing to paymore for beef of known tenderness.Although consumers are the ultimate judgesof tenderness, Warner-Bratzler shear force isa highly repeatable and economical methodfor measuring tenderness. Reviews of pub-lished literature on the genetic control oftenderness show that the heritability ofWarner-Bratzler shear force is moderatelyhigh (29%) and that of marbling is high(38%), indicating that progress can be madethrough selection. However, selecting forpalatability is difficult and expensive. EPDshave become “user friendly” tools for cattle-men to use in selecting for numerous traits,but until the implementation of this project,no cattle breed association had EPDs forWarner-Bratzler shear force or sensory-evaluated palatability traits. Recently, theAmerican Simmental Association publishedWarner-Bratzler shear force EPDs as a resultof this project. DNA markers have beenidentified at Texas A & M University fortenderness and other quality traits and, if


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validated in this project, could be used in‘marker-assisted’ selection. With EPDsand(or) DNA marker-assisted selection, thebeef cattle industry then can make significantprogress toward improving meat palatabilitythrough genetic selection.

The Carcass Merit Project is an extensive3½ year project involving four universities,15 beef cattle breed associations (16 breeds),and Celera AgGen. The project is funded andcoordinated by NCBA and the Cattlemen’sBeef Board, the breed associations, andCelera AgGen. Its objectives are:

1. Collect information to develop EPDs forcarcass merit traits.

2. Measure longissimus lumborum (stripsteak) Warner-Bratzler shear force ofcontemporary groups of progeny frommultiple sires within each breed.

3. Measure longissimus lumborum sensoryattributes on a sample of contemporarygroups of progeny from sires included inDNA ‘marker’ validation.

4. Validate DNA markers to be used inindustry-wide ‘marker-assisted’ selectionprograms for improvement of carcassmerit traits.

5. Determine DNA genotypes of theseprogeny for previously identified carcassmerit markers.

6. Measure direct and opportunity costs andreturns of implementing EPDs for car-cass merit traits.


The 15 breed associations (16 breeds) areproviding approximately 11,000 AI progenyof their more widely used sires, primarilyfrom commercial cow herds. One or morereference sires of each breed is used in a testherd in which a breed is being tested (refer-ence sires are used to tie contemporarygroups together for the breeds being tested).BIF guidelines for sire evaluation must befollowed. The number of progeny from eachbreed is determined by the number of regis-

trations of each breed calculated as a propor-tion of the total number registered by thecooperating breed associations. Each breedassociation is responsible for providingleadership for progeny testing; costs ofsynchronizing and mating cows; coordinat-ing progeny testing; blood sampling; feed-ing; carcass data collection; and the develop-ment of EPDs for their breed. Consequently,the breed associations are funding about 50%of the total costs. The NCBA is providingfunds for shear force and sensory panelevaluation, graduate student assistantships,travel for carcass data collection, and one-half of the DNA analyses. Celera AgGen isfunding the other half of the DNA analyses.Sires will be compared only within breedand NOT across breeds . Breed identity iscoded to prevent associations or breedersfrom comparing breeds. Dan Moser is thefacilitator and liaison to the breed associa-tions.

The selection of test herds, sires, feedlotsand feedlot regimen, slaughter endpoint, andprocessing plants are at the discretion of eachbreed association.

Each association is allocated a minimumof 10 sires plus additional sires, based on thenumber of registrations for each breed,resulting in 10 to 54 sires per association.Ten sires within each breed will be desig-nated as DNA sires, with a target of 50progeny per sire. For non-DNA sires, thetarget is 15 progeny per sire, although this isat the discretion of each breed association.Carcass and Warner-Bratzler shear force dataare obtained on all progeny from all sires.For five of the DNA sires within each breed,trained sensory panel evaluations will beconducted on all progeny. Progeny data canbe accumulated over the 3½ year period, aslong as reference sires are repeated. Prior toor upon entering the feedlot, blood samplesare sent to both Clare Abbey at Texas A &M and to Tom Holm at Celera AgGen foranalyses. Semen samples are also analyzedfor the DNA sires. The DNA analyses are tovalidate the presence of ‘markers’ for shearforce, sensory panel traits, and carcass traitsthat have been identified by Jerry Taylor andScott Davis at Texas A & M through thecheckoff and the Texas A & M-funded Ge-nome Mapping Project.


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A small muscle tissue sample from allprogeny is obtained at the time of slaughterfor backup DNA analyses and verification ofanimal identity. Detailed carcass data areobtained after chilling. One steak from eachprogeny of every sire and two steaks fromprogeny DNA sires are obtained and shippedovernight to Michael Dikeman at KansasState University for Warner-Bratzler shearforce and sensory panel evaluation. Shearsteaks are cooked at 14 days postmortem.Sensory panel steaks are frozen and laterthawed for trained sensory panel evaluations.

The database maintained by John Pollakat Cornell University is secure and updatedalmost daily. The development of carcass,shear force, and sensory panel EPDs is theresponsibility of the breed associations,although John Pollak will be conductingthose analyses for at least two breeds. TheNCBA and breed associations own all car-cass, shear force, and sensory panel data.Marker identities, genotypes produced byscoring the markers, and protocols formarker identification remain the property ofTexas A & M and NCBA. However, thisinformation, as well as the phenotypic data,will be provided to the breed associations fortheir use in computing EPDs.

Economic analyses will be conducted bySteve Koontz at Colorado State University.The first phase will measure direct costs ofdeveloping carcass merit EPDs and imple-menting management systems necessary touse the information. The second phase willmeasure the expected returns forimplementing a carcass merit-based produc-tion system. The third phase addresses themarketing system for cattle, carcasses, andmeat.

Elizabeth Westcott, the NCBA projectcoordinator, is responsible for implementa-tion and oversight of the project. An NCBAProducer Steering Committee consists ofKathy Hawkins, chair, from MI; Rob A.Brown from TX; Dave Nichols from IA;James Bradford from IA; John Grande fromMT; and James Bennett from VA. That

Committee is responsible for giving over-sight as needed and providing insight onfuture use of the DNA information.

Preliminary Results

To date, carcass and Warner-Bratzlershear force data have been collected on over4,300 cattle. Sensory panels have evaluatedsteaks from over 1,500 cattle. Warner-Bratzler shear force EPDs have been devel-oped and published for 47 Simmental and 10Simbrah sires and are reported in the follow-ing paper in this report. Publishing EPDs forshear force is a first for the beef industry.Several other breeds may be developingEPDs within the year 2001. For breeds inwhich sufficient progeny have beenslaughtered, variation appears sufficient toallow for genetic progress.

Several breeds have provided enoughprogeny to date for complete DNA analyseson several sires. A minimum of 66 markersare to be screened for each sire (11 Quantita-tive Trait Loci, QTL). There are seven QTLsfor shear force and sensory panel tenderness,three for marbling, and one for ribeye area.The markers are not genes, but are randomsegments of DNA found at specific loca-tions. Validation will determine if the QTLdiscovered in the Texas A & M experimentusing Angus and Brahman cross cattle segre-gate within the various breeds in this projectand, if so, which are heterozygous. In anexample where a sire is heterozygous for amarker, such as Warner-Bratzler shear force,the progeny with markers that flank the QTLon one of the pair of chromosomes will beassociated with having a lower or highershear force value than those with the othermarkers. Therefore, DNA marker analysiscould be used in selection, if a sire is hetero-zygous for the QTL of interest.

Some markers identifying QTL havebeen validated in several sires of the breedswhere DNA analysis is complete. This sug-gests that the markers can be used as a selec-tion tool for at least some traits for sires ofsome breeds.


1Professor of animal breeding, Cornell University.2Executive Director, American Simmental Association.3Associate Director for Research & Technical Services, National Cattlemen’s Beef Association.

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CARCASS MERIT TRAITS: DEVELOPMENT OFEPDS FOR WARNER-BRATZLER SHEAR FORCE

AND DNA MARKER VALIDATION

M. E. Dikeman, E. J. Pollak 1, S. L. Stroda,R. J. Lipsey 2, and E. A. Westcott 3

Summary

Warner-Bratzler shear force data on striploin steaks were obtained on 761 steers fromcontemporary groups of progeny from themost popular 38 Simmental sires, and 133steers from nine Simbrah sires. The rangefor Warner-Bratzler shear force EPDs for theSimmental sires was from -0.51 lb (moretender) to +0.48 lb (less tender). The range inEPDs for the Simbrah sires was from -0.73to +0.73 lb. In addition, DNA analyses andscreening have been completed for 11 quan-titative trait loci on several Simmental andSimbrah sires. Information from this projectshould allow cattle producers to improvecarcass traits, tenderness, and other palatabil-ity traits through classical genetic selectionor through DNA marker-assisted selection.

Introduction

The Carcass Merit Project is described inthe preceding article. The specific objectivereported here was to measure longissimusmuscle (strip loin steak) Warner-Bratzlershear force and to calculate EPDs based on761 progeny from 38 Simmental sires and133 progeny from nine Simbrah sires.


Strip loin steaks were obtained from 761progeny of the 38 most widely used Sim-mental sires and 133 progeny from nine of the

most widely used Simbrah sires, both matedto commercial cows. Steaks were retrieved atthe time of carcass data collection. One ormore reference sires was used in each testherd. BIF guidelines for sire evaluation werefollowed. Steaks were vacuum packaged andaged at 33-37°F until 14 days postmortem.They were cooked in a Blodgett oven at325°F to an endpoint temperature of 158°F.Eight ½-inch cores were removed andsheared on an Instron Universal TestingMachine using the Warner-Bratzler sheardevice. Researchers at Cornell Universityconducted the genetic evaluations and calcu-lations of EPDs, using a heritability estimateof 30% for Warner-Bratzler shear force.

Preliminary Results

Table 1 lists Simmental and Simbrahsires that had seven or more progeny evalu-ated, their sire and maternal grandsire, theirEPDs, the EPD accuracy, and the number ofprogeny slaughtered. The most tender Sim-mental sire had an EPD for Warner-Bratzlershear force of -0.51 lb and the least tendersire had an EPD of +0.48 lb. The most tenderSimbrah sire had an EPD of -0.73 lb and theleast tender, +0.73 lb. The accuracies arerelatively low for some of the sires becauseof small progeny numbers. The differencesin the accuracy values are somewhat analo-gous to meteorologists predicting a 20%versus a 40% chance of rain. In other words,an accuracy of 0.42 means that the EPD value is


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more reliable than one with an accuracy of0.16. The differences in these EPD valuesare large enough to allow for genetic im-

provement in tenderness when used in selec-tion, particularly in the Simbrah breed.

Table 1. Simmental and Simbrah Sire Names, Their Sire and Maternal Grandsire, Expected ProgenyDifference, Accuracy, and Number of Progeny Evaluated

WBSF1 No. of Simmental Sire Name Sire/Maternal Grandsire EPD Accuracy Progeny3C Pasque 8773 Mr Abondance/Siegfrieds Powerthe 0.03 0.33 223C Wally C240 Emmons Black Hercules/HPS Night Rider 0.35 0.26 13ALR Mr Lincoln Cherithbrook Mr Abe/DS Polltime 0.24 0.16 9ASR Cactus Red Z002 Polled Stretch/Alpine Polled Proto 0.3 0.35 42Black Irish Kansas Irish Black Knight/Kansas Black Jim -0.09 0.42 37Black Mick Black Knight U2/Irish Rover -0.04 0.31 20Bold Future Bold Ruler/H&S Pete 0.28 0.33 20Boz Red Jet Red Brother/Landridge Jet Black -0.01 0.2 9Burns Bull X339U Black Max/Buck 0.14 0.29 17Charles Pride Copper Black S72/Landridge Jet Black 0.2 0.39 28Circle S Leachman 600U Landridge Jet Black/Steelman -0.41 0.46 50DS Zinger 141B Hercules 538P/3X 0.15 0.29 15DS Pollfleck 809 ABR Sir Arnold G809/Urspring -0.24 0.29 15Emmons Black Hercules Landridge Jet Black/Hercules 538P -0.21 0.31 21ER Americana 537B Black Max/Hercules 538P -0.11 0.26 13ER Big Sky 545B ER Black Mack 568Y/Siegfried -0.2 0.36 26ER Mackfrid 550B ER Black Mack 568Y/Siegfried -0.25 0.32 21F Nichols Black Advantage Nichols Dynamite 9X/Buck -0.18 0.33 19Five Oaks Black Stretch Polled Stretch/Buck -0.35 0.21 11GW Tailor Made 515A Meyers Black Equalizer/T N T Mr T 0.45 0.27 16HF/GF1 Powerline 7F MV Red Light 406/Black Max -0.51 0.23 11J&C Black Maxi Van J & C Black Maximizer W5/Extra -0.19 0.21 17Klondike Arnie GNM 250Z SRF Mr Bigfoot S138/Bold 0 0.33 21KSR Dr Pepper D405 Red Pepper/Grand Desire 0.03 0.27 21LSR Preferred Stock 370C Circle S Leachman 600U/Irish Black Knight -0.16 0.28 12Meyers Blacktop 206Y Buck/Eagle -0.33 0.31 17Meyers Red Top Meyers Blacktop 206Y/Chocolate Chip K34 -0.21 0.26 11Nichols Big Easy D56 Nichols Dynamite 9X/Leachman Blk Baron 235X -0.16 0.16 9Nichols Black Destiny D12 CircleS Leachman 600U/Buck -0.08 0.44 59Nichols Blockbuster D100 Nichols Dynamite 9X/Buck -0.3 0.25 30Nichols Prime Rib E160 Nichols Prime Rib C139/F Nichols Black Advantage -0.05 0.3 51NLC Good A Nuff 33G NLC 64 Tomcat/Leachman Red Baldy 438W 0.02 0.27 25PVF-BF26 Black Joker Harts Black Casino B408/Hercules 538P -0.13 0.16 7SRS Franchise F601 LRS Preferred Stock 370C/Meyers Black Power -0.13 0.19 8SSS Craftsman 004F DS Black Zinger 141B/Black Polled Dakota 0.48 0.19 8SV Red Charlie Charles Pride/TT Red Delight 0.12 0.22 8TKBS Mr Pride F164 Charles Pride/Meyers Blacktop 206Y 0.13 0.21 8WHF Desperado 212G PLT Cutting Edge D209/LRS Preferred Stock 370C 0.11 0.15 7Simbrah Sire Name

HR Nile King PRR King Aurthur/Mr Pete 535P 0.46 0.31 21K Bar Southern Comfort RBR Leggacy/Red Rajah -0.32 0.26 14LL&L Blaze of Mississip Mississippi 0.44 0.24 12LMC Accountant 5A/174 LMC Money 8412P/5P Baliia 659 0.73 0.28 17LMC Energizer 5B/155 Sir Nick 24Y/Wards Bravo 1/09 0.05 0.13 8Parthenon Matador B218 K Bar Southern Comfort/Counter Sign -0.48 0.29 18PRR Pacesetter 205C ISB MrX108X/RBR Net Profit -0.06 0.28 16RX Banner's B200 RX Polled Banner Zo2/AFI Honcho Supreme -0.47 0.25 13RX Colorado C332 HS Nail Z490 Abundance/RX Cognac 202 -0.73 0.26 141Warner-Bratzler shear force.


1North Central Research and Outreach Center, University of Minnesota, Grand Rapids, MN.2Northwest Area Extension Office, Colby.

9


OVULATION SYNCHRONIZATION WITH PROGESTINSPRIOR TO A COSYNCH PROTOCOL IN BEEF COWS

J. S. Stevenson, M. A. Medina-Britos,A. M. Richardson, G. C. Lamb 1, B. A. Hensley,

T. J. Marple, and S. J. Johnson 2

Summary

A multi-location study was conducted usingsuckled beef cows in Minnesota and Kansas totest the benefit of adding a source of progestinto the Cosynch ovulation synchronization proto-col (injections of GnRH, 7 days before and 48hr after an injection of PGF2", with a fixed-timeartificial insemination (AI) administered at thesame time as the second GnRH injection).Feeding melengestrol acetate (MGA) for 14days followed in 12 days by the Cosynch proto-col was compared to the Cosynch protocol withthe addition of a progesterone-impregnatedinsert (CIDR) placed in the vagina for 7 daysconcurrent with the first GnRH injection.Pregnancy rates after the first AI (timed AI)were 22% greater with the CIDR insert, where-as conception rates for those cows returning toestrus were greater for cows previously fedMGA. Total pregnant cows after two insemina-tions were 64% for CIDR cows and 59% forMGA cows.

(Key Words: Ovulation Synchronization, Cows,Embryo Survival, MGA, CIDR.)

Introduction

During the past 6 years we have experi-mented with various hormonal protocols tosynchronize estrus and ovulation in suckled beefcows without calf removal. Using an injectionof GnRH 7 days before an injection of PGF2",has successfully increased the percentageof cows showing heat during the firstweek of the breeding season, the per-

centage of cows cycling, and the percentageof cows conceiving to a fixed-time insemination.

Further improvement in these results hasoccurred when a progestin treatment was in-cluded during the 7 days before PGF2".Norgestomet ear implants and the intravaginalprogesterone-impregnated CIDR insert haveserved this purpose. In combination withGnRH, the progestin exposure reduces the shortestrous cycles that sometimes follow GnRH-induced ovulation in suckled cows.

The objective of the present experiment wasto determine whether or not feeding melengestr-ol acetate (MGA; orally active progestin) wouldserve a similar purpose as the CIDR insert.Neither the norgestomet implant nor the CIDRare market-available. However, it is anticipatedthat the CIDR insert (Pharmacia & Upjohn,Kalamazoo, MI) may be available later thisyear. It is not known whether the norgestometimplant (part of the Syncro-Mate B estrus-synchronization system) will return to the mar-ket.


We used 609 suckled beef cows in twotreatments at four locations (Kansas StateUniversity Purebred Beef Unit, Manhattan, KS;Thielen Ranch, Dorrance, KS; North CentralResearch and Outreach Center, GrandRapids, MN; and DarLynn Ranch, Pierz,MN). The two treatments are illustratedin Figure 1. In the first treatment, cows


10

were fed MGA (0.5 mg per cow per day) for14 days, followed in 12 days by the first injec-tion of GnRH, followed in 7 days by an injectionof prostaglandin F2" (PGF2"), followed in 48 hrby a second GnRH injection at the same time astimed artificial insemination (TAI). The secondtreatment consisted of feeding the carrier with-out MGA for 14 days, with the injections as forthe MGA treatment. In addition, cows receivingno MGA received a new intravaginalprogester-one-releasing insert (CIDR®-1380insert, Hamilton, New Zealand) containing 1.38g of progesterone on day -7 and removed onday 0. The diets of all cows were supple-mented with grain mix or a premix containing 4lb of a pelleted formulation that contains either0 or 0.5 mg of MGA for a 14-day feeding (days-33 to -19).

MGA GnRH+ TAI

GnRH 9MGA 9 PGF2" 9

| | | | |!33 !19 !7 0 +2

CIDR GnRH+ TAI

GnRH 99 PGF2" 9

| | | | |!33 !19 !7 0 +2

B B B* B

Days from PGF2""

(beginning of the breeding season)

* = Body condition scoresB = Blood sample to determine concen-

tration of progesterone= 0.5 mg of melengestrol acetate per

day= New CIDR (1.38 g of progester-

one)

Figure 1. Experimental Protocol.

Blood samples were collected at days !19,!7, 0, and +2 for later analysis of serum pro-gesterone. Body scores were assessed onday 0. Cows were observed for returns to

estrus beginning 20 days after the TAI andcontinued until day 23. Cows were inseminatedbetween 8 and 12 hr after first detected returnto estrus. Pregnancy diagnoses were made bytransrectal ultrasonography on days 29-33 (alllocations) and again on days 57-61 (threelocations) afte r TAI. Pregnancy rates werecalculated as the number of cows determinedpregnant divided by the number of cows treatedand inseminated. Embryo loss was calculatedfor cows in which two pregnancy diagnoseswere made.


Number of cows, breed composition, bodycondition scores, and days postpartum at theonset of the breeding season are summarized bylocation in Table 1.

Results for all locations combined are sum-marized in Table 2. Pregnancy rates after thefirst TAI were greater (P<0.05) for cows treat-ed with the CIDR insert than after feedingMGA. This difference was consistent at threeof four locations, whereas at location D, preg-nancy rates were identical between treatments.

Rates of return to the first eligible estrus andaverage interval to estrus after the first insemina-tion were not different between treatments.

Conception rates of cows that were re-inseminated were 22% greater (P<0.05) inthose previously fed the MGA than those re-ceiving the CIDR inserts. However, becausethe reverse was true for pregnancy rates at theTAI, the total proportion pregnant after twoinseminations was similar between treatments.

About 11% of the embryos first detected byultrasonography on days 29-33 did not surviveto days 57-61 when the second diagnosis ofpregnancy was measured.

Our results from past studies have clearlydemonstrated that pregnancy rates achievedafter the Cosynch protocol (injections of GnRH7 days before and 48 hr after an injectionof PGF2", with a fixed-time AI adminis-


11

tered at the same time as the second GnRHinjection) are variable. Pregnancy rates rangedfrom 30 to 55%. When a progestin (onenorgestomet ear implant or a CIDR) is includedin the system during the 7 days between theinjections of GnRH and PGF2", pregnancy ratesranged from 55 to 66%.

The present study demonstrates again thatthe addition of a progestin produces pregnancyrates >50% after a TAI (2000 Cattlemen’sDay, pp 104-106). Response to the

MGA + Cosynch protocol was less at threelocations, but at one location it was equal to thatof the CIDR insert. Some difficulty arises whenattempting to feed MGA to cows once theyhave been moved to pasture. The carrier forthe MGA must be highly palatable and easy tofeed in pasture situations. In contrast, the costof feeding MGA may be less than the cost ofthe inserting the CIDR.

Table 1. Characteristics of Synchronized Suckled Cows

Location

Trait A B C D Total

No. of cows 149 161 81 218 609

Breed composition Crosses of:Angus, SouthDevon, andCharolais

PurebredSimmental,Hereford,and Angus

Angus Crosses of:Simmental,Hereford,and Angus

Body condition score atonset of breeding season 5.4 4.7 5.2 5.1 5.1

Days postpartum at onsetof breeding season 69 79 86 70 75

Table 2. Reproductive Traits of Suckled Cows

Treatment

Trait CIDR MGA

No. of cows 304 305

Pregnancy rates after first AI, % 55 45*

Rates of return to estrus after first AI, % 58 57

Average days to return estrus after first AI 21.3 21.4

Conception rates after second AI, % 50 61*

Total pregnant after two inseminations, % 64 59

Embryo survival after days 29-33 to days 57-61, % 90 88

*Different (P<0.05) from CIDR treatment.


1North Central Research and Outreach Center, University of Minnesota, Grand Rapids, MN.2Northwest Area Extension Office, Colby.

12


RESYNCHRONIZATION OF ESTRUS WITHPROGESTERONE AND ESTROGEN IN

PREVIOUSLY INSEMINATED BEEF COWS

J. S. Stevenson, M. A. Medina-Britos,A. M. Richardson, G. C. Lamb 1,

B. A. Hensley, T. J. Marple, and S. J. Johnson 2

Summary

A study was conducted in 609 beef cows todetermine whether or not estrus might beresynchronized in previously inseminated beefcows to accommodate a second artificial insem-ination (AI) early in the breeding season. Previ-ously inseminated cows were treated for 7 dayswith progesterone (via a previously used intra-vaginal progesterone-releasing insert [CIDR])beginning 13 days after AI. In addition, injec-tions of estrogen (estradiol benzoate [EB] orestradiol cypionate [ECP]) were given at inser-tion and removal of the CIDR insert. Rates ofreturn to estrus and total pregnancy rates wereincreased after treatments with progesteroneand estrogen compared with controls. No harmto pregnancies occurred in pregnant cows anda second AI period was facilitated by the end ofthe first 23 days of the breeding season.

(Key Words: Cows, Resynchronization ofEstrus, Estrogen, Progesterone, PregnancyRates.)

Introduction

Unfortunately, the pregnancy outcome afterfirst inseminations is unknown until cows have arepeat estrus (20 to 22 days after first service),are diagnosed pregnant at about 28 days viatransrectal ultrasonography, or are diagnosed bypalpation after 35 to 40 days. In all such cases,the full advantage gained from synchronizingfollicular maturation and luteolysis is not fully realized.

Because all cows are closely synchronized afterfirst insemination, all open cows can easily beresynchronized for their second (and evensubsequent) services.

At least two approaches have been at-tempted to set up a resynchronization of sec-ond services. The first attempt included reinser-tion of a progesterone-releasing intravaginaldevice or the feeding of a progestin after previ-ous inseminations. Results were variable.

A second approach included administrationof supplemental progestin plus estrogen (tocontrol follicular growth) at the time of insertionof a progesterone-releasing device, and estro-gen administration (to induce estrus and thepreovulatory LH surge) 0 or 24 hr after theprogesterone insert is removed. In those stud-ies, estradiol benzoate (EB) was used. The onlyestrogen product available in the U.S. isestradiol cypionate (ECP®, Pharmacia &Upjohn Co., Kalamazoo, MI). Using a combi-nation of estrogen and progesterone to resetfollicular dynamics and synchronize the nexteligible estrus has met with success in dairycattle. Inseminated cows were exposed toprogesterone (a used CIDR) for 7 days be-tween days 13 and 20 after insemination. Thesetreatments did not reduce pregnancy rates ofdairy cows that had conceived at first servicebut increased the probability that allnonpregnant cows exhibited estrus within 3 daysafter progesterone withdrawal, or within 2 daysif a second estrogen (EB) injection was given 0to 24 hr after progesterone withdrawal. Only rarely


13

do pregnant cows show estrus in response tothis treatment.

The purpose of our study was to determineif resynchronization of estrus with progesteroneand estrogen was feasible in pregnant andnonpregnant suckled beef cows without harm tothe ongoing pregnancy of pregnant cows.


We used three resynchronization treatmentson the 609 suckled beef cows described in theprevious report (see pages 9 to 11). The threetreatments are illustrated in Figure 1.

Timed AI Control9 Detect estrus| | | and AI |0 +13 +20 +23

Timed AI EB9 EB EB

9 9 Detect estrus| | | and AI |0 +13 +20 +23

Timed AI ECP9 ECP ECP

9 9 Detect estrus| | | and AI |0 +13 +20 +23

B B B

Days from TAI

B = Blood sample to determine concen-tration of progesterone

= Used CIDR (1.38 g of progester-one)

EB = Estradiol benzoate (1 mg)ECP = Estradiol cypionate (0.5 mg)

Figure 1. Experimental Protocol.

Thirteen days after AI, 50% of the cowsreceived no further treatment (controls); 25%

received 1 mg of estradiol benzoate (EB) plus aused CIDR (progesterone-releasing intravaginalinsert originally containing 1.38 g of progester-one; CIDR®-1380 insert, Hamilton, NewZealand); and 25% received 0.5 mg of estradiolcypionate (ECP) plus a used CIDR. Sevendays later, the controls received no furthertreatment. The used CIDR was removed fromEB cows and they received an additional 1 mgof EB. The used CIDR was removed fromECP cows and they received an additional 0.5mg of ECP.

Cows were observed for estrus twice dailybetween 20 and 23 days after the timed AI.Any cow detected in estrus after the second EBor ECP injection was re-inseminated between 8and 12 hr later. Blood samples were collectedprior to each injection of estrogen (EB or ECP)for later analysis of serum progesterone. Preg-nancy diagnoses were made by transrectalultrasonography on days 29-33 (all locations)after timed AI (6 to 10 days after the secondestrogen injection) and again 31 to 34 dayslater.


Results of this experiment are summarized inTable 1. The resynchronization protocols werenot detrimental to already pregnant cows be-cause pregnancy rates after the first timed AIwere similar for two estrogen treatments com-pared to the controls.

Rates of return to estrus were increased bymore than twofold (EB = 2.7×; ECP = 2.3×)with the use of the used CIDR and estrogentreatments. Average days to returned estrusafter the timed AI were greater (P<0.01) for thelonger-acting estrogen (ECP) than for theshorter–acting estrogen (EB). Conception ratesof cows after treatment with progesterone andestrogen tended (P=0.11) to be less than thoseof controls, primarily because of the EB sourceof estrogen. Most importantly, total pregnantcows after two syncronizations and insemina-tions was increased by 11-23%. Embryo sur-vival was unaffected by estrogen treatments.These results demonstrate that repeat estrus canbe successfully resychronized after a timed AI programby using a combination of a CIDR and either of


14

two estrogen products. Estradiol benzoate hasbeen used successfully in similar protocols forseasonal-calving dairy cows in New Zealandand Australia. Unfortunately, EB is not avail-able in our market, but ECP is available to“correct anestrus (absence of heat period) in theabsence of follicular cysts in some cases” (la-beled indication for ECP®; Pharmacia & Upjoh-n , K a l a m a z o o , M I ) .

Even though the treatment is given to all cowsregardless of pregnancy status, no harm oc-curred to the ongoing pregnancy in our study orin other studies. In fact, the total number ofpregnancies was increased after using ourprotocol so that more than 60% of the cowswere pregnant to AI sires after 23 days of thebreeding season.

Table 1. Reproductive Traits of Suckled Cows after Resynchronization with the CIDR(Progesterone) and Estrogen

Treatment

Trait Control EB ECP

No. of cows 189 96 94

Pregnancy rates after first AI, % 52 44 51

Rates of return to estrus after first AI, % 27X 73 63

Average days to return estrus after first AI 21.3 21.2Y 21.7

Conception rates after second AI, % 62Z 48 63

Total pregnant after two inseminations, % 56X 62 69

Embryo survival after days 29-33 to days 57-61, % 84 92 96

XControl vs. estrogen (EB+ECP) (P<0.01).YEB vs. ECP (P<0.01).ZControl vs. estrogen (EB+ECP) (P=0.11).


15


TIMED-INSEMINATION OF BEEF HEIFERS USING COSYNCH WITH OR WITHOUT MGA

D. M. Grieger, T. A. Wickersham and R. C. Cochran

Summary

Our purpose was to determine if feedingmelengesterol acetate (MGA) for 1 week incombination with gonadotropin-releasing hor-mone (GnRH) and prostaglandin-F2" (PGF)would better synchronize heifers for timedartificial insemination. Sixty-nine yearling beefheifers received an injection of GnRH 7 daysbefore receiving an injection of PGF. Half of theheifers were fed MGA between the GnRH andPGF injections (Cosynch+MGA), whereas theremaining heifers were not (Cosynch). Allheifers were given a second GnRH injection 2days after PGF and inseminated at that time.Pregnancy rate for the Cosynch group (43%)was greater (P<0.05) than that for theCosynch+MGA group (15%). This experimentsuggests that short-term feeding (7 days) ofMGA in concert with a Cosynch protocol wasdetrimental to fertility in beef heifers.

(Key Words: Heifers, AI, Synchronization,MGA, GnRH, PGF2")

Introduction

Previous research at Kansas State andother locations has shown that using combina-tions of GnRH and PGF has resulted in preg-nancy rates ranging from 40-60% with timedinsemination of lactating mature beef cows.However, using these same protocols in heifersresults in pregnancy rates at least 10% lower.In mature cows, the better pregnancy rates(>50%) have resulted from protocols using aprogestin (e.g., ear implant of norgestomet or anintravaginal insert containing progesterone)between the initial GnRH injection and the PGFinjection. Therefore, we conducted this experi-ment using an oral progestin (MGA) combined with

GnRH and PGF to see if timed inseminationresults for beef heifers could be improved.


Sixty-nine crossbred yearling beef heifers(avg 735 lb) received an injection (i.m.) ofGnRH (100 µg Cystorelin®; Merial Ltd., Iselin,NJ), on day !7. One week later (day 0), allheifers received 25 mg of PGF (Lutalyse®;Pharmacia & Upjohn, Kalamazoo, MI) fol-lowed by a second injection of GnRH (100 µg)on day 2. All heifers were inseminated at thetime of the second GnRH injection. This ovula-tion synchronization protocol is referred to asCosynch. Half of the heifers (n=34) were fedMGA (0.5 mg/head/day) for 7 days from day!6 until day 0 (see Figure 1). The remainingheifers (n=35) received the same supplementwithout MGA. Blood samples for later mea-surement of progesterone were collected atdays !18, !7 and 0 to determine the number ofpubertal animals prior to treatment. Pregnancywas determined in all heifers 30 days afterinsemination using ultrasonography.


Prior to the first GnRH injection (Day !7)there was no difference in the number of heiferscycling between the Cosynch (86%) and theCosynch+MGA (91%) groups. The pregnancyrate for heifers in the Cosynch+ MGA treatment(15%) was lower (P<0.05) than that for theCosynch treatment group (43%). FeedingMGA during the first week of the Cosynchtreatment was detrimental to fertility in theseheifers. This study indicates that MGA may notbe a suitable progestin to use in combinationwith Cosynch. The timed insemination mayhave been too soon after MGA with-drawal. Long-term fertility was not affected


16

however, as overall pregnancy rates at the endof a 45-day pasture-breeding season were thesame for the Cosynch+MGA group (88%) as

compared to the heifers that did not receiveMGA (91%).

GnRH

GnRH PGF and AICosynch Preg rate = 43% (n=34)

day !7 day 0 day 2

GnRH GnRH PGF and AICosynch+MGA

MGA Preg rate = 15%

(n=35)

day !7 day 0 day 2

Figure 1. Synchronization Treatments and Pregnancy Rates for Cosynch vs. Cosynch+MGA.


17


SHORT-TERM FEEDING OF MGA TO POSTPARTUMCOWS PRIOR TO THE BREEDING SEASON

J. F. Gleghorn, T. T. Marston,and L. E. Wankel

Summary

A protocol to make anestrous cows morelikely to cycle prior to estrous synchroniza-tion would greatly enhance reproductiveefficiency. Ease of application, availability,and low cost make feeding melengestrolacetate (MGA) a good choice in such aprotocol. MGA, used as a progestin“primer,” has no detrimental effects on cowsthat are already cycling and reduces thenumber of cows expressing short cycles.

(Key Words: MGA, Postpartum Interval,Pregnancy Rate, Short Cycle.)

Introduction

Fifteen to twenty percent of the nation’scows fail to wean a calf annually, primarilybecause they do not become pregnant withinthe relatively short breeding season. Thepurpose of our experiments was to test aprotocol that would “progestin-prime” multi-parous beef cows so that all would be cy-cling at the start of the breeding season. Sucha procedure would be useful in many opera-tions that are unable to justify labor-intensivesynchronization systems.


Experiment 1Thirty-nine multiparous, crossbred cows

were exposed to progestin (MGA) treatmentbeginning 30 days postpartum (Spring,1999). Cows were blocked according tocalving date and assigned randomly to treat-ment. Treatments consisted of feeding MGAfor 8, 4, 2, or 0 (controls) days at 0.5mg/head daily.

Blood was collected before and afterMGA supplementation and analyzed forprogesterone concentration (>1 ng/ml wasevidence for luteal activity).

Cows were synchronized with prosta-glandin F2" (Lutalyse®, Pharmacia &Upjohn) at the beginning of the breedingseason, inseminated upon standing heat, andexposed to bulls 6 days following the secondLutalyse injection. Pregnancy and concep-tion dates were determined by uterine palpa-tion and actual calving dates.

Only cows anestrus before treatmentwere included in the statistical analysis ofinitial rise in blood progesterone, days toconception, incidence of short cycles, andresponse to prostaglandin F2". However, bothcycling and noncycling cows at 30 dayspostpartum were included in determinationof pregnancy rates and conception rates toAI.

Experiment 2Ninety-three multiparous, black baldy,

fall-calving cows were used in 1999. Cowswere assigned randomly to receive MGA(0.5 mg per head daily for 4 days) (n=44) orno MGA (n=49). Suckled cows grazedfescue pastures and were group-fed thesupplement. Treatment began 35 days priorto the breeding season. Bull exposure wasfor 60 days.

Experiment 3Thirty-six multiparous Angus and Angus

× Hereford cows were used in April 2000.Cows were blocked by calving date andassigned randomly to MGA (0.5 mg per headdaily for 4 days) or no MGA. Suckled cowswere individually fed the MGA supplement


18

starting 30 days prior to the breeding season,while grazing native grass pasture. Bullexposure was for 60 days.


Experiment 1Blood samples revealed 20.5% of cows

were cycling 30 days prior to the beginningof the breeding season. Cycling percentagesfor each treatment group were: 33% (8 days),20% (4 days), 18% (2 days), and 11% (0days).

Treatment with MGA influenced (P<.05)days to the first postpartum luteal activity(progesterone>1 ng/ml) (Table 1). The 0-and 2-day treatments produced earlier(P<0.05) postpartum rises in serum proges-terone than either 4- or 8-day treatments. Atrend was also noted in days from MGAwithdrawal to progesterone rise. The 2-daytreatment increased blood progesterone 3.6days following withdrawal. The 4- and 8-day treatments delayed first luteal activity to11.7 and 13.5 days, respectively. Treatmenthad no effect on days to conception follow-ing calving.

The incidence of short cycles tended todecrease (P=0.28) with increased days ofMGA treatment. Ninety-one percent of thecontrols exhibited short cycles, versus nonefor 8-day MGA-treated cows.

A decrease in calving interval was notedwith MGA treatment. The 2-day cows aver-aged 355 ± 7 days between calves, whereascontrols averaged 377 ± 8 days (P<0.10).The other treatments (4 day and 8 day) wereintermediate; 366 ± 8 days and 371 ± 8 days,respectively.

An overall pregnancy rate of 92% wasachieved for all cows. The percentages ofcows artificially inseminated were greater inMGA-treated cows than controls. More(P<0.05) 2-day MGA-treated cows (86%)were inseminated during the AI period thancontrols (33%).

Experiment 2Pregnancy rates were similar for control

(95%) and MGA-treated (97%) cows (Table2). Fetal ages (by palpation) were similarbetween treatments.

Experiment 3An overall pregnancy rate of 88% was

achieved for all cows. Pregnancy rates weregreater (P<0.05) for MGA-treated cows(100%) than for controls (76%). Neitherdays pregnant (fetal age) nor calendar date ofconception was influenced by MGA treat-ment.

It is clear that progestin is necessary forthe induction of normal estrous cycles inpostpartum beef cows. Whether the progestinis from an endogenous source or exogenoustreatment (MGA), progestin is necessary toprepare the female reproductive tract for thesubsequent pregnancy. It is thought thatprogesterone acts as a “primer” to enablegonadotropins to regulate reproductive func-tion. The decrease in short, non-fertile cy-cles achieved by feeding MGA is of interest,because decreasing short cycles tightens thecalving season. Progestin may also elicitmore distinct estrus response from hormonalchallenge, and possibly improve conceptionrates to AI at the beginning of the breedingseason.


19

Table 1. Effects of Temporal Feeding MGA to Postpartum Cows (Experiment 1)

Days MGA Fed

Item 0 2 4 8

Calving to 1st luteal activity, days 38.8a 34.8 a 45.0b 48.5b

1st Luteal activity following the end of MGAfeeding, days

-- 3.6 11.7 13.5

Cows exhibiting a short cycle, % 91 53 32 0

AI pregnancy rates, % 33 86 57 63

Subsequent calving interval, days 377 355 366 371a,bMeans with uncommon superscript letters differ (P<0.05).

Table 2. Effects of Feeding MGA Prior to the Breeding Season

Days MGA Fed

0 4

Experiment 2, Fall-calving Cows

Pregnancy rate, % 95 97

Fetal age, days 85 82

Days postpartum conceived 84 88

Experiment 3, Spring-calving Cows

Pregnancy rate, % 76 100

Fetal age, day 68 70


1This research was supported by Beef Checkoff program funds.2Department of Agricultural Economics.

20


FACTORS AFFECTING BEEF DEMAND 1

J. Mintert 2, T. Schroeder 2, and T. Marsh 2

Summary

We investigated factors that have af-fected beef demand over the last two de-cades. Beef demand is typically modeled asa function of beef prices, competing meatprices, prices of all other goods, and con-sumer expenditures. Our comprehensivemodel also investigated the impact on beefdemand of food safety issues, health con-cerns, and changes in consumer lifestyle anddemographics. Results from this analysishelp explain changes in beef demand thatoccurred during the 1980s and 1990s. First,consumer concerns about food safety, asmeasured by increases in beef recalls, had anegative impact on beef demand over the lasttwo decades. Second, consumer awarenessof the linkage between cholesterol and heartdisease also contributed to the decline in beefdemand. In contrast, as the net number ofmedical journal articles linking cholesteroland heart disease increased, poultry demandactually increased. Finally, increased laborforce participation by females had a negativeimpact on beef demand, because an increasein female employment outside the homelikely resulted in a decline in time availablefor food preparation. Because poultry de-mand benefitted from this consumer demo-graphic shift and because of beef's negativehealth image, these results suggest that beefindustry efforts to provide consumers withmore convenient, high quality products havelagged behind those of the poultry industry.

(Key Words: Beef Demand, Food Safety,Health Concerns, Consumer Demographics.)

Introduction

Beef demand improved modestly during1999 and 2000, increasing an average ofabout 4% in each of the last 2 years. How-ever, prior to the recent rebound, the beefindustry was plagued with nearly 20 years ofdeclining demand. Inflation-adjusted, retail-beef prices were collapsing at the same timeper capita consumption was declining. Forexample, a beef-demand index that accountsfor changes in per capita beef consumptionand inflation-adjusted, retail-beef pricesindicates that 1998 Choice retail-beef priceswere 50% lower than they would have beenif beef demand had been held constant at its1980 level (Figure 1). If the beef industry isto successfully improve long-term demand,the impact of individual demand determi-nants on beef demand must be quantified.Our study was designed to determine themajor factors causing beef demand to shiftover time.

Procedures

It is impossible to accurately assignrelative demand shifts to individual demanddeterminants through casual observation oftrends and beef demand shifts because manybeef-demand determinants, as well as beefproduction, change at the same time. As aresult, a meat demand system was estimatedusing quarterly time series data over the1982 through the 1998 period. The systemincluded factors accounting for prices ofcompeting meats and total consumer expen-ditures, changing consumer demographics,


21

food safety problems, health information,and seasonality.


Our model indicates that beef demand isinelastic with respect to beef price and thatpork and poultry are weak substitutes forbeef. From 1982 through 1998, on average,beef quantity demanded declined 0.61%given a 1% increase in beef price. Responsesto competing meat-price changes were muchsmaller. Beef quantity demanded increased0.04% and 0.02%, given a 1% increase inretail pork and poultry prices, respectively.These elasticity estimates indicate thatalthough relative prices matter, per capitabeef consumption is not highly responsive tochanges in pork and poultry prices. More-over, beef expenditures represent a progres-sively smaller proportion of total consumerexpenditures. This implies that beef demandcould become even more inelastic (i.e.,quantity demanded could be less responsiveto price changes) in the future.

Beef demand is highly responsive tochanges in total per capita expenditures onall goods. Changes in total per capita expen-ditures occur when personal disposableincome increases, consumer willingness tospend income increases, or a combination ofthe two. Consumer willingness to spend alarger proportion of total income has been animportant source of economic growth for theU.S. economy in recent years. For example,consumer expenditures rose from less than90% of disposable income in the early 1980sto near 98% by 1999. Demand-model resultsindicate that beef demand increases 0.90%for a 1% increase in total per capita expendi-tures. This means that beef demand was amajor beneficiary of increasing consumerexpenditures. However, if consumers chooseto increase savings in the future (in lieu ofconsumption), or if disposable income de-clines, it will have a negative impact on beefdemand.

Beef demand declines when beef-safetyrecalls occur. Beef recalls averaged 2.1 perquarter from 1982 through 1998, but thenumber of recalls varied across quarters andyears. For example, beef recalls ranged from4 to 8 per quarter during 1998. Over the1982 through 1998 period, the number ofFood Safety Inspection Service recalls wererelatively few in number and their impact onbeef demand was generally small. But thedemand model indicates that a large increasein beef recalls can lead to an economicallysignificant downward shift in beef demand.

Health information linking cholesteroland heart disease weakened beef demand,from 1982 through 1998, by about 0.60%annually. As more medical journal articlesare published linking cholesterol and heartdisease, beef demand declines modestly,whereas pork and poultry demand actuallyincrease. Importantly, the negative impact ofheath information on beef demand increasedover the study period.

Changing demographics suggest thatconsumers are placing more emphasis onhow quickly meat items can be prepared forconsumption. The percentage of females inthe labor force rose from 52% in 1982 to60% in 1998. As a greater proportion offemales enter the labor force, less time isavailable for at home food preparation. Thischange had a negative effect on beef de-mand, but a positive effect on poultry de-mand. Beef demand declined an average of1.3% annually over the 1992-99 period as aresult of an increasing female labor force.Assuming that consumer demand for conve-nience is related to female labor force partic-ipation, this suggests that the poultry sectorbenefitted over time by offering more conve-nient products to consumers. At the sametime, beef demand suffered through 1998 astime allocated for food preparation declinedand the beef industry failed to offer consum-ers high quality, convenient, easy-to-preparebeef products.


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4080 82 84 86 88 90 92 94 96 98 00

YearSource: USDA, Dept. of Commerce and K-StateResearch & Extension, 2000 partially estimated.

Figure 1. Choice Retail Beef Demand Index, 1980 = 100.


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1Department of Agricultural Economics.2Department of Economics, Iowa State University.

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MOTIVATION FACTORS FOR BEEFPROCESSOR-PRODUCER LINKAGES

T. C. Schroeder 1, J. D. Lawrence 2,and M. L. Hayenga 2

Summary

A survey was conducted of the 15 largestbeef processors to identify the mix of pro-curement practices being used and to under-stand reasons motivating recent processor-producer linkages. Processors are shiftingaway from cash-market live, fed-cattle trade,which represents only 36% of cattle procuredby survey respondents in 1999. Processor-owned cattle feeding represents only approx-imately 5%, where it has been for more thana decade. Various other forms of pricingsuch as carcass weight, grid, and formularepresented the largest portion of purchasesat 49%. Processors indicated the two mostimportant reasons they get involved in con-tracts and marketing agreements with pro-ducers is to secure higher and more consis-tent quality cattle. Assuring food safety wasalso a motivation for linking more closelywith cattle producers. In the future, proces-sors felt these motivational factors wouldincrease in importance. As cattle feedersexplore grid pricing and alliance opportuni-ties, it is important they understand whyprocessors desire to enter into contracts andmarketing agreements.

(Key Words: Beef Processors, Contracts,Marketing Agreements, Cattle Marketing.)

Introduction

The U.S. beef industry is undergoingmarked transitions in the way livestock andmeat products are marketed and the wayprice discovery occurs. The once dominant

negotiated cash markets are shifting to long-term contracts and marketing agreements.The purpose of this study was to determinecurrent marketing and pricing methods beingused by beef processors. The current andexpected mix of pricing methods for fedcattle were estimated by the processors. Inaddition, major motivating factors forchanging beef processor-producer linkageswere assessed.

Results of this study will contribute to abetter understanding of the important coordi-nation mechanisms that affect market effi-ciency and performance in these industries.This study will also offer insights into thechanging industry organization that will beuseful in strategic planning by industrymembers. The complexities of mandatorylivestock- and meat-price reporting (fromrecent federal legislation) will become moreclear as the variety of methods employed inthe marketing system are documented. Fi-nally, the information from these surveysshould be useful in assessing issues raised incourt cases alleging illegalities associatedwith "captive supplies" in the beef industry,and proposed legislation to eliminate proces-sor vertical integration and long-term con-tracts with livestock producers.

Procedures

During April 2000 the largest 15 beefprocessing firms were surveyed to determinecurrent procurement practices and to discernprocessor perceptions on why the beef valuechain has moved to more formal agreements.


24

Survey responses were received from 11 ofthe 15 packing firms, representing 72% ofcattle slaughtered. The processors weretelephoned, asked to participate in the study,and were faxed a survey form.


Processors are shifting away from livecattle cash market purchases to more long-term contractual and/or value-based gridpurchases. However, negotiated cash marketpricing arrangements still remain dominant.Only 5% of cattle slaughtered by surveyrespondents were owned by them and eitherfed in their own lots or other feedlots. Thisrepresents little change over the last 15years. In 1999, survey respondents reported36% of cattle were purchased on the cashmarket on a live weight basis, and 29% on acarcass weight or grid (carcass merit) basis(Table 1). Thus, approximately two-thirds ofcattle slaughtered were cash market acquisi-tions.

Long term (more than 14 days) formula-priced contracts linked to the cash marketaccounted for 20 percent of 1999 purchases.“Cash market” included live cattle or whole-sale beef prices reported by USDA, proces-sor cattle purchase cost averages, retail beefprices, or futures market prices. Four per-cent of cattle purchased were via short-termcontract arrangements based on the ChicagoMercantile Exchange (basis contracts, orfixed price based on futures-market prices,with deliveries typically several months inthe future). Three percent of the cattle wereacquired under risk and profit-sharing, mar-ket contract arrangements with cattle feeders,but not owned by processors while in thefeedlot.

Cash market purchases by processorbuyers are based on their expectations oflikely carcass quality. However, a largenumber of cattle feeders sell all of their pens,perhaps with several owners, at the same liveor carcass price, allowing little distinctionfor quality on a lot-by-lot, or carcass-by-

carcass basis. Cash market purchases basedon carcass merit are increasing in the cashand contract markets. In 1999, at least 35%of cattle purchased on contract or in the cashmarket were priced based on carcass meritbut some processors did not break that out intheir responses. Most cattle fed by proces-sors were also transferred to their processingoperations based on carcass merit.

Processors were queried regarding theimportance of specific reasons they andcattle producers enter into contracts andmarketing agreements. The two most impor-tant reasons cited by processors were to“secure higher quality cattle,” and to “securemore consistent quality cattle” (Table 2).Both of these responses had an average scoreof 4.0, with 1 being not important to 5 beingvery important. These were also expected tobe most important (and even more importantat 4.2) in 2004. Improving risk management,reducing plant operating costs by maximiz-ing slaughter plant capacity utilization, andassuring food safety were the next mostimportant reasons (average scores of 2.8 to3.0 in 1999). All three of these items alsoare expected to become more important, with2004 ratings for food safety at 3.7 and plantoperating efficiency at 3.5. The low impor-tance (average score of 1.8) attached to theassertion that contracts enabled processors topurchase cattle for a lower price may bebecause contracts and agreements do notenable processors to lower prices paid forcattle, as shown in recent USDA-sponsoredstudies. Securing adequate cattle quality andquantity are the primary factors motivatingbeef processor use of contracts and market-ing agreements with cattle producers.

Processors perceived that producers’primary incentives to enter into contracts andmarketing agreements were to secure aquality premium and obtain a higher pricefor cattle (Table 3). Processors felt that, inthe next five years, producers would benefitfrom marketing agreements primarily forthese reasons, as well as to obtain detailedcarcass data.


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Table 1. Percentage of Cattle Procured via Various Methods, 1999

Procurement Method PercentCash-market purchases on live weight basis 36Cash-market purchases on a carcass-weight or grid basis 29Formula-priced contract purchases based on a reported live cash market, reported dressed price, plant average price, CME cattle futures price, quoted boxed beef ,or retail-beef price

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Processor-fed cattle 5Fixed-price or basis-contract purchases based on CME futuresRisk-sharing contract purchases

43

Other purchases 4Total 100

Table 2. Processor Survey Responses Regarding Importance of Contract andMarketing Agreement Incentives to Beef Processors a

Importance to Processors1999

Average2004 Expected

AverageReduce plant operating costs due to improved slaughter plant capacity utilization 2.9 3.5Secure higher quality cattle 4.0 4.2Secure more consistent quality of cattle 4.0 4.2Assure food safety 3.0 3.7Improve long-run price-risk management 2.8 3.1Improve week-to-week supply/price management 2.2 2.9Reduce costs of searching for cattle to procure 2.3 2.4Able to purchase cattle for lower price 1.8 1.8aScale: 1 = not important, 5 = very important.

Table 3. Processor Survey Responses Regarding Importance of Contract andMarketing Agreement Incentives to Cattle Producers a

Importance for Producers1999

Average2004 Expected

AverageSecure a buyer for cattle 2.6 2.8Secure a quality premium/discount 4.0 4.0Reduce price risk 3.3 3.3Reduce costs of searching for a cattle buyer 2.4 2.8Able to sell cattle for higher price 3.8 3.8Easy to get loans 3.1 3.4Provide detailed carcass data 3.4 3.6aScale: 1 = not important, 5 = very important.


1Sincere appreciation is expressed to National Farms, Cottonwood Falls, and S-Bar Ranch Feedlot,Sublette, for providing cattle facilities and assistance and to Schering-Plough Animal Health forfinancial support.2South Central Area Extension Office, Hutchinson.3County Extension Agricultural Agents in Chase and Butler Counties, respectively.4Technical Services Nutritionist, Schering-Plough Animal Health.

26


EVALUATION OF RALGRO® ON PASTURE AND SUBSEQUENT FEEDLOT PERFORMANCE AND

CARCASS MERIT OF MEXICAN CROSSBRED STEERS 1

D. A. Blasi, S. I. Paisley 2, G. L. Kuhl, M. E. Dikeman, J. Higgins, G. L. Huck, M. S. Holder 3, D. E. Kehler 3,

T. B. Farran, J. J. Sindt, S. P. Montgomery, and C. Birkelo4

Summary

A pasture/feedlot field study was con-ducted to evaluate the effects of a singleRalgro® implant during the stocker phase onsteer grazing performance and subsequentfeedlot performance and carcass merit. Atotal of 2,764 steers of Mexican origin aver-aging 449 lb were assembled in Texas andshipped to Kansas, where they grazed onthree intensively-early-stocked Flint Hillspastures. At initial processing, the steerswere individually weighed and randomlyassigned to either a non-implanted controlgroup or a Ralgro implant group. Ralgrosteers gained more (23 lb; P<0.01) thancontrols during the 82- to 93-day grazingphase. Following the grazing phase, all steerswere shipped to a commercial feedlot insouthwestern Kansas where steers from eachpasture were individually weighed and givena single Component E-S® implant. Immedi-ately after processing, steers from eachpasture were sorted into either a light- orheavy-weight pen, regardless of pastureimplant treatment, resulting in six feedlotpens. Days on feed ranged from 127 to 197.Control steers gained faster (P<0.01) duringthe feedlot phase; however, Ralgro steers hadhigher cumulative weight gains across thecombined pasture and feedlot phases(P<0.01) and averaged three fewer days onfeed (P<0.05). There were no significantdifferences for marbling, fat thickness, rib-

eye area, KPH fat, or yield grade. Ralgrosteers had lower (P<0.05) quality gradesbecause of a higher incidence (P<0.001) ofsteers with B and C carcass maturities.

(Key Words: Growth Implant, Ralgro,Steers, Pasture, Feedlot, Carcass Traits.)

Introduction

Previous studies have demonstrated thatthe growth benefit obtained with pastureimplants is generally retained through thefinishing phase, provided sufficient hor-monal stimulation is maintained by a feedlotimplant program. Our objective was to eval-uate the effects of a single Ralgro implantadministered during the stocker phase onsteer grazing performance and subsequentfeedlot performance and carcass merit.


A total of 2,764 steers from Mexico wereassembled, vaccinated against common viraland bacterial diseases, and backgrounded inTexas until shipment to Kansas. The studywas initiated during April, 1999, using threeFlinthills pastures, and concluded with thefeedlot phase ending Jan./Feb., 2000.

Pasture phase - As cattle were delivered tofacilities adjacent to designated pastures,they were individually identified with two


27

numbered ear tags, alternately allotted to oneof two treatments (Ralgro or no implant)and weighed. Steers averaged 449 lb ini-tially across all pastures, and they grazedburned or unburned native grass Flint Hillpastures for 82 to 93 days (Table 1). Uni-form health and management procedureswere used throughout the study. Grazingperformance was calculated using individualweights taken immediately prior to turnoutand during initial processing at the feedlot.

Feedlot phase - Steers from each pasturewere shipped to a single feedlot in south-western Kansas. All were dewormed andimplanted with one Component E-S implant,and individually weighed and sorted intoeither a heavy or a light pen based on desiredout-weight (total of six pens). Feedlot gainwas based on a carcass-adjusted final weightusing the average dressing percentage deter-mined for each pen.


Table 2 presents steer performance bytreatment during the successive phases.Initial pasture weights were similar (P=0.71)for both treatments. The increased weightgain (P<0.01) observed for Ralgro vs. con-trol calves (+23 lbs/11.44%) is consistentwith previously reported Kansas results.Sorting steers from each pasture into two

pens (heavy and light) based on initial feed-lot weight, created 100 lb difference in initialaverage pen weights. This difference in on-test weights translated into an added 21 to 31days on feed for the lighter pens. Daily gainsin the feedlot ranged from 2.78 to 3.12lb/day for the feeding period for all pens.

During the feedlot phase, the steers notimplanted on pasture gained about 16 lbmore than the Ralgro-implanted steers. Butat least 9 lb of that difference could be attrib-uted to the fact that the controls were fed anaverage of 3 days longer (160 vs. 163 days).Nevertheless, the steers implanted duringgrazing had higher cumulative (pasture plusfeedlot) weight gains (P<0.05).

Carcass weights of Ralgro-implantedsteers tended to be greater (P<0.10) thancontrols. There were no significant differ-ences in marbling, ribeye area, KPH fat, fatthickness, or yield grade. There was a de-crease (P<0.05) in quality grade in pasture-implanted steers. However, much of thatdifference may have been due to severequality grade discounts of a few cattle due tomaturity. There were more (P<0.01) pasture-implanted cattle with B maturity carcasses.Thus carcasses with slight and small mar-bling (Select and low Choice quality gradesfor A- maturity carcasses) are downgraded toStandard for B maturity.

Table 1. Grazing Performance of Ralgro-Implanted Steersa

Flint Hills Native Pastureb

Item A B C P-valueNo. steers on test 796 583 1385Prescribed burn Yes Yes NoGrazing days 87 93 82 Starting date April 23, 1999 April 20, 1999 April 7, 1999 Ending dateb July 18/19, 1999 July 21/22, 1999 June 24/28, 1999 Stocking rate, acres/steer 1.76 1.89 0.92c

Animal Performanced

Initial wt, lb 466e 462e 414f <0.01 Final wt, lb 684e 721f 574g <0.01 Pasture weight gain, lb 217e 258f 161g <0.01 Daily gain, lb/day 2.50e 2.78f 1.96g <0.01aOne-half of the steers from each pasture received one Ralgro implant at the initiation of grazing.bEnding weights were taken upon arrival at S-Bar feedlot, Sublette, KS. Dates reflect the dates thatcattle were removed from pasture, and weighed at the feedlot, respectively. cStocking rate does notaccount for adjacent brome pasture in C pasture. dLeast squares means for each pasture. e,f,gMeanswith unlike superscripts within rows differ (P<0.05).


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Table 2. Effect of Ralgro Implants During Grazing on Subsequent Feedlot Performanceand Carcass Merita

Pasture Implant Treatmentb

Item Control (no implant) Ralgro®c SE P-valueGrass Phase: No. steers 1316 1321 Initial wt, lb 448 447 1.6 0.71 Final wt, lbd 649 671 1.8 <0.01 Pasture weight gain, lb 201 224 1.1 <0.01 Daily gain, lb/day 2.28 2.54 0.013 <0.01Feedlot Phase: Initial wt, lbd 649 671 1.6 <0.01 Final wt, lbe 1132 1139 2.7 0.08 Feedlot days on feedf 163 160 0.3 <0.01 Feedlot weight gain, lb 484 468 2.3 <0.01 Daily gain, lb/day 2.99 2.94 0.015 <0.01 Cumulative (grass plus Feedlot) weight gain, lb 685 692 2.5 <0.05Carcass Merit: Carcass wt, lb 730 734 1.7 0.10 Dressing % 64.50 64.50 -- -- Marblingh 372 368 2.3 0.13 Fat thickness, in 0.47 0.48 0.005 0.25 Ribeye area, in2 12.68 12.67 0.041 0.81 KPH fat, % 2.12 2.11 0.012 0.85 Carcass Maturityg, actual head 0.0024 A 1296 1283 B 19 36 C 1 2 Yield grade 2.81 2.84 0.02 0.17 Quality gradei 460 451 3.1 0.05

aSteers grazed 3 intensive early stocked (IES) Flint Hills pastures for 82, 87, or 93 days.bLeast squares means.cSteers received one Ralgro® implant at the initiation of the grazing phase. All steers received oneComponent E-S® implant at initial feedlot processing.dEnding weights for all steers were taken upon arrival at S-Bar Ranch feedlot near Sublette, KS.eFinal weight calculated using hot carcass weight divided by pen average dressing percent.fDuring initial processing at the feedlot, cattle from each pasture were sorted by weight into heavyand light pens. Due to the additional weight gain while on pasture, implanted cattle were placedprimarily in heavy pens, resulting in differences in days fed between control and implanted steers.gCarcass maturity scores: A maturity = approx. 9 to 30 mo. of chronological age at slaughter,B maturity = approximately 30 to 42 mo., C maturity = approximately 42 to 72 mo. (USDA1997). Chi-square exact methods used.hMarbling score: 100 = Practically devoid00; 200 = Traces00; 300 = Slight00; 350 = Slight50; 400 =Small00 500 = Modest00; 600 = Moderate00

iQuality grade: 300 = Select, 400 = Select, 500 = Choice - , 600 = Choice0 , 700 = Choice+.


1Western Kansas Agricultural Research Center, Hays.

29


EFFECTS OF VACCINATING BEEF DAMSPRECALVING AND CALVES PREWEANING WITH

A PASTEURELLA HAEMOLYTICA VACCINE

L. E. Wankel, T. T. Marston, G. L. Stokka,T. G. Rozell, and J. R. Brethour 1

Summary

Our objective was to determine if vacci-nating dams precalving and calves pre-weaning for Pasteurella haemolytica couldeffect serum antibody titers in dams, and thepre- and post-weaning health and perfor-mance of their calves. Vaccination increasedserum antibody titers in multiparous cows,but not first-calf heifers. Precalving vaccina-tion had minimal effects on mortality andmorbidity of calves before or after weaning.Subsequent steer feedlot gains were unaf-fected by precalving and preweaning vacci-nations and carcasses were not affected.However, heifers’ weight gains were greaterfrom weaning to one year of age when rearedby vaccinated dams.

(Key Words: Passive Immunity, Vaccina-tion, Antibody.)

Introduction

Pasteurella haemolytica is the majorpathogen in bovine respiratory disease inweaned beef calves. Vaccination has proveneffective in the prevention of P. haemolyticadisease. However, little research has beendone regarding the vaccine’s role in prevent-ing disease through passive immunity.Therefore, the objectives of our study wereto determine:

• if P. haemolytica vaccine could increaseserum antibody titers in beef cows

• if passive immunity would enhancedisease resistance and increase calf per-formance

• if preweaning P. haemolytica calf vacci-nation in conjunction with maternalprecalving treatments is effective.


In January 1999, multiparous (n=233)beef cows and primiparous (n=47) heifersreceived an injection of P. haemolyticavaccine (VAC) or no injection (CON) threeweeks prior to the start of the calving season.Blood samples were collected on the day oftreatment to establish existing serum anti-body titers. Three weeks post treatment,serum antibody titers were measured again toevaluate vaccine effectiveness. Titers weremeasured via enzyme-linked immunoassay.Calves were blocked statistically by cowtreatment and randomly allotted to receive P.haemolytica vaccine (VAC2) or no injection(CON2) three weeks preweaning. Thus, calftreatment groups were VAC/VAC2, VAC/CON2, CON/VAC2, and CON/CON2. Calfhealth and performance were evaluated frombirth to slaughter for steers and birth to oneyear of age for heifers. Steer carcass data andlung lesion scores were collected.


VAC multiparous cows (Figure 1) had agreater titer response than their non-vaccinated counterparts (P<0.05). However,the primiparous heifers did not respond tovaccination (P>0.13). Because primiparouscows were naive to P. haemolytica, thiscould have jeopardized their ability to signif-icantly increase serum titers.


30

b

a

No differences (P>0.64) in calf prewean-ing or postweaning illness or gain wererecognized. Steers were weaned and placedinto feedlot pens at the Western KansasAgricultural Research Center, Hays. Twoslaughter dates were used to optimize feedlotperformance and carcass traits. Steers aver-aged 469 ± 25 days of age and weighed 1320± 104 lb at slaughter. Feedlot gains were noteffected by dam or calf vaccination (P>0.48).There were no treatment differences in dress-ing percent, yield grade, marbling score, orback fat (P>0.23). There were also no differ-ences in number of lung lesions (P>0.51).However, heifers from VAC dams had great-er had greater (P<0.05) total postweaningweight gain (39.5 lb) than heifers from CON

dams. Most of the weight gain advantageoccurred during the second month afterweaning (P<0.05). Calf vaccination had noeffect on heifer performance (P>0.16).

Our data indicate that P. haemolyticavaccine increased serum antibody titers inmultiparous cows, but not in primiparousheifers. However, vaccination of calves hadlittle effect on their health status and perfor-mance, which could be attributed to the lowlevel of illness observed throughout thestudy. Perhaps under conditions of stressors,such as commingling, transportation, anddietary changes, vaccine effects would berecognized.

Figure 1. Serum Antibody Titers for Maternal Treatment Groups.a,b indicate statistical differences (P<0.05).


1County Extension Agricultural Agent, Clark County.

31


EVALUATION OF SOUTHWESTERNKANSAS NATIVE GRASSES

T. T. Marston and D. O. Yauk 1

Summary

Native grass samples were collectedmonthly for five years and analyzed fornutrient content. Crude protein and ADFcontent indicate that grass quality is highestin May and June, then steadily declines untilOctober. Stocker operators may need tobegin protein supplementation as early asJuly to sustain weight gains. Trace mineralvalues were erratic from year to year andmonth to month between and within years,indicating that trace mineral supplementationshould probably be maintained throughoutthe grazing season.

(Key Words: Native Grass, Protein, Miner-als, Nutrition.)

Introduction

Considerable data have been compiled onthe nutrient value of native grasses duringthe grazing season. From these data, supple-mentation programs have been recommend-ed for beef producers. Most Kansas data hascome from the Manhattan area or the West-ern Kansas Agricultural Research Center,Hays. Little information is available fromsouthwest Kansas. Our objective was tomeasure and record nutrient profiles ofnative grasses grown in Clark County, Kan-sas.


From May 1995 through October 1999,16- by 16-foot cages were placed in variousgrazing sites across Clark County. Siteswere selected to represent the different soil

types within the county. Once the cageswere in place, monthly samples (mid-May tomid-October) were harvested from within thecages. Grass species common to most of thesampling sites were little bluestem, side oatsgrama, blue grama, sand bluestem, andbuffalograss. Hand clipped samples were ofall standing plant material (dead and grow-ing) within a half inch of the ground. Sam-ples were weighed, sealed in plastic bags andsent to a commercial laboratory for analysis.Each year the cages were moved to a newsite within the same soil type. Samples wereanalyzed for dry matter, crude protein, aciddetergent fiber (ADF), calcium, phosphorus,copper, manganese, iron, zinc, and molybde-num contents. Data were combined acrosssoil types for reporting purposes.


Nutrient contents are summarized inTables 1, 2, and 3. There was considerablevariation from year to year and month tomonth, which was probably a reflection ofweather patterns. As native grasses maturethrough the grazing season, they decline incrude protein and increase in ADF. Cattleperformance would be expected to declinecorrespondingly. Research from KansasState and other universities has indicated thatsupplementing with degradable intake pro-tein should enhance cattle performance whenprotein requirements of the animal and itsrumen microflora are not met. Assumingthat a 600-pound, medium-framed steermight select a diet that contains 2% morecrude protein than our samples, and thatforage availability is non-limiting, producers


32

may need to consider protein supple-mentation as early as July if their goal is toobtain daily gains of 2 pounds or greater.This is earlier than most producers supple-ment stocker cattle in southwest Kansas.

Trace minerals can affect performanceand immunity status of the grazing animal.Our data indicated that content can be quite

variable for copper, manganese, zinc andmolybdenum. One third of the monthlycopper means (10 of 30 sample months)were less than 50% of the daily requirements(NRC, 1996). Because of the erratic changesin trace mineral content, it may be appropri-ate to provide 50 to 100% of the trace min-eral requirement of summer grazing animalsas a supplement.

Table 1. Statistical Values of Major and Trace Minerals from Native Grass SamplesHarvested During the Growing Season, Dry Matter Basis (1995-1999)

ItemNo. of

Samples MeanStandardDeviation Minimum Maximum

Calcium, % 273 0.51 0.20 0.14 1.56Phosphorus, % 274 0.15 0.05 0.06 0.32Copper, ppm 274 15.1 9.7 2.29 52.7Iron, ppm 274 306 164 60.6 1320Manganese, ppm 274 41.0 15.2 13.7 104.0Molybdenum, ppm 273 1.7 0.95 0.42 6.73Zinc, ppm 274 34.2 9.8 13.0 81.5

Table 2. Yearly Average Nutrient Content in Native Grass Samples Collected inSouthwest Kansas, Dry Matter Basis (1995 – 1999)

YearItem 1995 1996 1997 1998 1999Crude protein, % 6.57 7.66 6.16 6.30 5.70ADF, % 41.6 44.8 46.7 45.3 45.5Calcium,% 0.69 0.46 0.50 0.46 0.49Phosphorus, % 0.17 0.18 0.15 0.15 0.13Copper, ppm 13.3 10.4 8.8 15.9 24.4Manganese, ppm 45.8 33.9 37.1 38.6 48.8Zinc, ppm 32.1 31.6 29.8 35.1 40.5Molybdenum, ppm 1.41 1.52 1.98 1.65 1.91


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Table 3. Monthly Average Nutrient Content in Native Grass Samples Collected inSouthwest Kansas, Dry Matter Basis (1995-1999)

Month

Item: May June July Aug. Sept. Oct.

Crude protein, % 7.82 7.59 6.90 6.20 5.69 4.66

ADF, % 44.1 42.6 43.9 44.7 45.3 48.1

Calcium,% 0.56 0.24 0.52 0.51 0.48 0.50

Phosphorus, % 0.17 0.17 0.18 0.16 0.15 0.11

Copper, ppm 12.4 18.1 11.9 17.3 15.1 12.8

Manganese, ppm 50.0 42.1 39.9 39.0 34.0 40.2

Zinc, ppm 35.8 32.8 33.1 38.4 29.3 33.5

Molybdenum, ppm 1.33 1.67 1.84 2.03 1.68 1.61

Table 4. Percentage of Yearly and Monthly Trace Mineral Mean Values MeetingNRC Recommendations a

Percentage of Samples Greater than NRC Requirements

Copper Manganese Zinc

Yearly mean values:

1995 50.3 ± 1.4 69.9 ± 6.4 48.0 ± 5.4

1996 50.2 ± 1.3 35.5 ± 5.9 61.7 ± 5.0

1997 31.8 ± 1.2 28.3 ± 5.6 37.9 ± 4.8

1998 83.5 ± 1.1 35.2 ± 4.8 80.1 ± 4.1

1999 98.6 ± 1.1 63.9 ± 4.8 84.6 ± 4.1

Monthly mean values:

May 60.2 ± 1.3 65.8 ± 6.0 67.8 ± 5.1

June 60.2 ± 1.3 51.0 ± 6.0 59.1 ± 5.1

July 60.2 ± 1.3 48.5 ± 6.0 67.6 ± 5.1

August 58.4 ± 1.3 39.6 ± 6.0 67.3 ± 5.1

September 80.2 ± 1.3 31.0 ± 6.0 48.8 ± 5.1

October 58.0 ± 1.3 43.3 ± 6.0 64.2 ± 5.1aNCR (1996) mineral requirements: copper, 10 ppm; manganese, 40 ppm; and zinc, 30 ppm.


1Sincere appreciation is expressed to National Farms, Kansas City and S-Bar Ranch Feedlot, Sublettefor cooperation and to Schering-Plough Animal Health for financial support.2South Central Area Extension Office, Hutchinson.3Veterinary Medical Diagnostic Laboratory and Department of Biomedical Science, respectively,University of Missouri, Columbia, MO.4County Extension Agricultural Agents in Chase, Greenwood, and Butler Counties, respectively.5Department of Statistics.

34


A SURVEY OF PHYTOESTROGENIC ACTIVITY IN KANSAS FLINT HILLS PASTURES 1

D.A. Blasi, S. I. Paisley 2, W. V. Welshons 3,G. E. Rottinghaus 3, M. S. Holder 4, J. L. Davidson 4,

D. E. Kehler 4, and J. Higgins 5

Summary

The botanical composition and basalcover of three Kansas Flint Hills pastureslocated in Butler and Chase counties wassurveyed to estimate the incidence of plantspecies that contain appreciable levels ofestrogenic activity. Many-flowered scurfpeaand Ladino clover were the only plant spe-cies classified as high in estrogenic activity.Although significant estrogenic activityexisted in specific species, the willingness oflivestock to consume those species is un-clear.

(Key Words: Flint Hills Pastures, Phyto-estrogen, Buller Steer Syndrome.)

Introduction

Incidence of the buller steer syndrome infeedlots is typically less than 4%, but canoccasionally reach 10%. However, severalKansas feedlot managers have observedindividual pen bulling rates as high as 30%in steers previously grazed on Kansas FlintHills native pastures. Factors such as socialhierarchy, aggressive behavior, seasonality,entry weights, stress, pheromones, andgrowth promoting implants have been sug-gested as factors contributing to the occur-rence of the buller steer syndrome. Morerecently, plant estrogens have been impli-

cated as an additional factor that mightincrease bulling activity or reduce the effi-cacy of growth-promoting implants.

More than 40 plant species have beenshown to contain estrogenic activity. Estro-genic activity is widespread among manylegumes, including subterranean (Trifoliumsubterran), white (Trifolium repens), and red(Trifolium pratense) clovers, as well asalfalfa. Many leguminous plants, such aspurple prairieclover, Illinois bundleflower,catsclaw sensitive briar, showy partridgepea,and many-flowered scurfpea, naturally in-habit Flint Hills native-grass pastures. More-over, introduced species such as Koreanlespedeza, which was extensively air-seededduring the 1950's, may be present (Owensby,personal communication, 1999). However,it is not known if plant species found in FlintHills pastures contain estrogenic activity inappreciable concentrations or if they areconsumed in sufficient quantities to elicitbulling activity. Consequently, during Julywe determined the phytoestrogenic activityin a variety of pasture plants, as well as inalfalfa collected at a commercial feedlot.


Botanical composition and basal coverestimates from three pastures in the FlintHills were determined in July, 1999, using a


35

modification of the step-point system out-lined by Owensby (1973). Individual plantspecies were collected over three samplingperiods during the latter stages of intensive-early grazing (early to mid-July). All foragesamples were frozen and shipped overnightto a University of Missouri laboratory forphytoestrogen analyses.

The bioassay (Welshons et al., 1990; J.Vet Diagn Invest. 2:268) measures estrogen-stimulated growth of MCF-7 cells in tissueculture. It is both specific in that it detectsonly estrogens and inclusive, detecting allestrogenic compounds. The assay is excep-tionally sensitive, requires minimal samplepreparation, and allows a large number offeed/forage samples to be screened.


Table 1 illustrates the plant species com-position of the three Flint Hills pastures.Major warm season perennial grass such asbig bluestem, little bluestem, indiangrass andswitchgrass, represented about 70% of thethe plant species counted in pastures A andB, with leguminous plants and forbs repre-

senting 7 to 12%. Pasture C contained morecool season grasses, forbs and sedges.

Estrogenic activity varied dramaticallyamong the species assayed. Table 2 showsthe results of the bioassay expressed inzearalenone equivalents, which is the amountof zearlenone required to give the observedresponse. The highest estrogenic activitywas found in Ladino clover and many-flow-ered scurfpea (Psoralea tenuiflora Pursh).Intermediate levels of activity were found inalfalfa, black medic, and Korean lespedeza.Because Korean lespedeza is an introducedspecies, its presence is variable and dependsupon the original seeding. Low levels ofactivity were found in roundhead lespedeza,wood sorrel, and yellow sweet clover. Onlytraces of activity were found in the grasses.

Native and introduced legumes com-prised only 3 to 4% of the plant species inthe three pastures we studied. This raisesquestions regarding their potential contribu-tion to the buller steer syndrome. Collectingsamples throughout the grazing season andmeasuring actual plant selection by animalswill answer that question.

Table 1. Plant Species Composition of Three Flint Hills Pastures (1999)

PastureA B C

-------------- Count (Percentage)--------------------Major warm seasona 72.24% 70.27% 58.74%Minor warm seasonb 12.07% 12.41% 10.72%Cool seasonc 2.24% 0.86% 7.15%Misc. grassd 2.41% 0.86% 1.94%Forbse 3.28% 5.78% 8.39%Native Legumef 4.14% 2.99% 3.26%Sedge 3.62% 6.84% 9.79% Total 100% 100% 100%aBig blue, little blue, indian, switch. bBuffalo, grama, sideoats. cAnnual, fescue, Brome,Poa. dPanic, dropseed. eAnnual, field pussytoe, ragweed, aster, oxalis, yarrow, Goldenrod,daisy fleabane, milkweed, dandelion, many-flowered scurfpea, wood sorrel, westernyarrow, western ragweed, showy partridge pea, purple prairie coneflower, Illinoisbundleflower, catsclaw sensitive briar, California loosestrife. fBlack medic, Koreanlespedeza, iron weed, leadplant, ladino clover, roundhead lespedeza.


36

Table 2. Zearalenone equivalent of Kansas Flint Hills Native Plant Species

Zearalenone Equivalent, ppm dry basis

Plant SpeciesNo. of

Samples Rangesa Average Range

Ladino clover 5 high 10.9624 2.032 - 36.239

Many-flowered scurfpea 2 high 43.6929 39.39 - 47.9958

Alfalfa hay 6 medium 7.5120 3.103 - 13.051

Black medic 9 medium 5.0318 1.037 - 15.429

Korean lespedeza 13 medium 8.4032 0.8063 - 27.558

Blue wild indigo 1 low 3.2650 3.265

Roundhead lespedeza 3 low 1.2004 0.4266 - 2.355

Wood sorrel (oxalis) 1 low 1.9690 1.969

Yellow sweet clover 1 low 1.0140 1.014

California loosestrife 1 < 1 ppm 0.0412 0.0412

Catsclaw sensitive briar 9 < 1 ppm 0.0513 0.0133 - 0.145

Grazed grass 8 < 1 ppm 0.1063 0.0274 - 0.2602

Illinois bundleflower 3 < 1 ppm 0.2454 0.225 - 0.7363

Leadplant 11 < 1 ppm 0.2766 0.0831 - 0.595

Non-grazed grass 2 < 1 ppm 0.0186 0.0212 - 0.01602

Purple prairie clover 4 < 1 ppm 0.0771 0.0311 - 0.121

Sedge 1 < 1 ppm 0.1780 0.178

Showy partridge pea 1 < 1 ppm 0.7039 0.7309

Ungrazed grass 2 < 1 ppm 0.0120 0.01089 - 0.0131

Western ragweed 3 < 1 ppm 0.7760 0.293 - 1.041

Western yarrow 3 < 1 ppm 0.1077 0.0596 - 0.174aHigh = >10 ppm; medium = >5 and <10 ppm; low = >and < 5ppm.


37


INFLUENCE OF LOW-LEVEL FALL SUPPLEMENTATION WITH A SELF-FED, HIGH-PROTEIN SUPPLEMENT AND LEVEL OF

WINTER SUPPLEMENTATION ON PERFORMANCE OF BEEF COWS GRAZING TALLGRASS-PRAIRIE RANGE

T. A. Wickersham, R. C. Cochran, D. V. Dhuyvetter, D. M. Grieger, and C. G. Farmer

Summary

An experiment was conducted to deter-mine the effect of providing a small amountof a high-protein supplement during the falland effects of increasing subsequent level ofwinter supplementation on cow-calf perfor-mance. One hundred-sixty spring-calvingHereford × Angus cows grazing tallgrass-prairie range were used. During the fall,cows either had access to a self-fed, high-protein supplement (30% CP) or were notsupplemented. During the winter, rangecubes (20% CP) were fed at a daily equiva-lent of 1, 2, 3, or 4 lb/head and all cows hadaccess to the same self-fed supplement usedduring the fall period. Cumulative perfor-mance (as measured by changes in bodycondition score and body weight) tended toshow limited response to low-level fallsupplementation, but was significantly im-proved as level of winter supplementationincreased.

(Key Words: Protein, Range, Beef Cattle,Supplementation, Self-Feeding.)

Introduction

During the period between weaning andinitiation of winter supplementation, aspring-calving cow’s nutrient demands aretypically at their lowest, enabling cows torecover body weight and condition beforeentering winter. However, forage proteinconcentration during this period is often lowenough to prevent optimum utilization ofavailable nutrients, hampering the cow’sability to improve body condition. Previousresearch at Kansas State University demon-strated that utilization of low-quality forageis improved by protein supplementation, with

the greatest improvements from the firstincrements of supplement. Our initial objec-tive was to evaluate the capability of smallquantities of a self-fed, high-protein supple-ment to improve forage utilization during thefall period, thereby increasing the cow’sability to recover condition during this pe-riod and enabling her to enter winter in betternutritional status. Improved condition andweight entering the winter period may re-duce the amount of supplementation requiredto maintain desirable levels of performance.Therefore, an additional objective was toevaluate the response to increasing levels ofwinter supplement among groups of cowsmanaged both with and without fall supple-mentation.


During the fall and winter of 1999-2000,160 Hereford × Angus cows were used toexamine the effect of different fall and win-ter supplementation treatments on perfor-mance. Cows were weighed and body condi-tion scored (1 = extremely emaciated, 9 =extremely obese) on October 4, 1999, strati-fied by body condition score and bodyweight, and assigned randomly within stratato one of four pastures. Initial conditionscore averaged 5.2 and initial body weightaveraged 1,139 lbs.

Pasture groups were randomly assignedto two fall (10/4/1999 through 11/30/1999)treatments (two pasture groups per treat-ment); either free-choice access to a highprotein (30% CP) self-fed, cooked molassessupplement or no supplementation. In addi-tion, within each pasture group, cows werestratified by body condition and weight andrandomly assigned within strata to one of


38

four winter (12/1/1999 to calving)supplementation treatments; free-choiceaccess by all cows to the same self-fed sup-plement used during the fall period plus anaverage daily equivalent of 1, 2, 3, or 4lb/head of a commercial range cube (20%CP). Range cubes were delivered on Mon-day, Wednesday, and Friday and were pro-rated to match the described daily intakeaverages. On supplementation days, all cowswere gathered and sorted into their appropri-ate treatment groups and group-fed theirsupplement. Intake of the self-fed supple-ment was regulated throughout the fall andwinter periods by manipulating container(250 lb tubs) placement and/or number. Ourintended consumption was 0.5 – 1.0 lb/headdaily. Consumption of the self-fed productwas measured through both fall and winterperiods, ending in late February with thebeginning of the calving season.

After calving (average calving date =3/5/00) all cows continued to graze tallgrass-prairie, but were switched to a commonsupplementation program (12 lb/head dailyof high-quality alfalfa hay) until sufficientgreen grass was available (mid- to late-April). In addition to the initial weight andbody condition measurement in early Octo-ber, cows were weighed and body conditionscored again on November 30, January 6,February 8, within 48 hours after calving,May 9, and at weaning (10/4/2000). Calveswere weighed within 48 hours after calving,on May 9, and at weaning. Pregnancy ratewas determined by rectal palpation at wean-ing.


Daily intake of the self-fed supplementby cows during the fall period averaged 1.40lb/head, slightly higher than the targetedconsumption level (Table 1). However, fallsupplementation under our conditions did notsignificantly improve body condition scorechange or weight change. Daily intake of theself-fed supplement during the winter period

was not affected (P=0.54) by previous falltreatment (approximately 0.95 lb/head).Increasing level of range cube supple-mentation decreased cumulative body condi-tion loss and cumulative weight loss (linear,P<0.01) during the winter period (Table 2).Although cow performance during the fallperiod was not significantly altered by con-sumption of the self-fed supplement, bodyweight at calving for supplemented cowstended (P=0.08) to be heavier.

Only one interaction (P=0.05) was ob-served; BCS for the fall-supplemented groupwas slightly higher across all winter supple-ment levels except at the highest level ofwinter supplementation.

Changes in BCS and BW after calvingtended (P#0.06) to be inversely related toBW and BCS changes during the prepartumperiod. As a result, cows supplementedduring the fall or those receiving morewinter supplement tended (P#0.08) to losemore body condition, or show less improve-ment in body condition, from calving throu-gh May 9. Increasing the level of wintersupplementation linearly increased calf birthweight (P=0.02). Neither fall nor wintersupplementation treatments elicited a re-sponse in calf ADG from birth until weaning(10/4/200). Fall supplementation had littleeffect on percent of cows pregnant at wean-ing. However, it is noteworthy that thelowest level of winter supplementation ex-hibited the lowest pregnancy rates, being atleast nine percentage units lower (Table 5)than other treatments. Differences betweenwinter supplementation treatments weresignificant (P=0.04).

This experiment indicated that althoughmost performance characteristics were im-proved in proportion to level of wintersupplementation, providing a limited amountof protein for a short period during the fallexerted only minimal effects on subsequentlivestock response.


39

Table 1. Effect of Fall Supplementation and Subsequent Winter SupplementationLevel on Changes in Fall Body Weight (BW), Condition Scorea (BCS), andSelf-Fed Supplement Consumption of Beef Cows Grazing Dormant,Tallgrass-Prairie Forage

Treatment

ItemNo Fall

SupplementationFall

Supplementation SE Pb

No. of Cows 80 80

Initial BCS 5.20 5.21 0.038 0.89

Period BCS change

4 Oct – 30 Nov -0.16 -0.07 0.049 0.34

Initial BW, lb 1131 1147 5.8 0.20

Period BW change, lb

4 Oct – 30 Nov 15 22 14.8 0.79

Self-fed supplement consumption, lb/d

4 Oct – 30 Nov -- 1.40 -- --

1 Dec – 22 Feb 0.92 0.99 0.067 0.54aBody condition scale: 1=extremely emaciated; 9=extremely obese.bProbability of a greater F-value.


40

Table 2. Effect of Fall Supplementation and Subsequent Winter Supplementation Level onChanges in Cow Body Condition Scorea (BCS), Cow Body Weight (BW), and CalfPerformance for Beef Cattle Grazing Tallgrass-Prairie

Treatment

No Fall Supplementation Fall Supplementation

lb/head/day lb/head/day

Item 1 2 3 4 1 2 3 4 SE

No. of Cows 20 20 20 20 19 20 20 20

Initial Cow BCS 4.98 5.05 5.08 5.09 5.15 5.16 5.21 5.09 0.081

Initial Cow BW, lb 1112 1172 1137 1165 1162 1168 1171 1175 12.3

Cow Performance - Cumulative Changes

BCS 12/1 – Calvingb -1.55 -1.30 -1.01 -0.86 -1.47 -1.34 -0.84 -0.93 0.094

BW 12/1 – Calvingb -228 -201 -154 -152 -224 -207 -159 -138 12.5

BCS Calvingc 3.43 3.75 4.06 4.23 3.70 3.83 4.38 4.13 0.061

BW Calving, lbb 879 972 983 1014 938 961 1012 1037 11.3

BCS Calving – 5/9 0.22 0.19 -0.13 0.14 0.13 0.06 -0.02 -0.19 0.126

BW Calving – 5/9b -24 -48 -74 -52 -28 -47 -62 -87 10.1

Cow Weaning BCS 5.13 5.15 5.18 5.30 5.24 5.19 5.24 5.17 0.081

Cow Weaning BW, lb 1106 1172 1136 1188 1179 1151 1167 1183 21.1

No. of Cows Calving 19 20 19 20 18 20 20 19

Calf Performance

Birth wt, lbd 81.3 84.2 82.3 89.4 84.6 84.3 87.0 86.6 1.66

Calf Weaning BW, lb 514 516 548 542 534 533 550 538 11.9

Calf ADG, lb 2.04 2.03 2.13 2.14 2.13 2.12 2.18 2.13 0.040

aBody condition scale: 1 = extremely emaciated; 9 = extremely obese.bContrasts for supplementation level across fall supplementation treatments were linear (P<0.05).cInteraction between fall and winter supplementation was significant (P<0.05); additionally, linear,quadratic, and cubic contrast for supplementation level across fall supplementation treatments weresignificant P<0.05).dContrasts for supplementation level across fall supplementation treatments were linear (P<0.05).


41

Table 3. Effect of Fall Supplementation and Subsequent Winter Supplementation Level onChanges in Cow Body Condition Scorea (BCS), Cow Body Weight (BW) fromOctober 4, 1999 to October 4, 2000 on Beef Cattle Grazing Tallgrass-Prairie

Treatment

No Fall Supplementation Fall Supplementation

lb cube/head/day lb cube/head/day

Item 1 2 3 4 1 2 3 4 SE

Initial Cow BCS 5.26 5.23 5.13 5.18 5.15 5.32 5.20 5.18 0.053

Initial Cow BW, lbb 1103 1158 1118 1147 1135 1147 1151 1155 8.9

Cow Performance - Cumulative changes

Change in BCSc -.14 -.08 .15 .12 .04 -.16 .04 -.05 0.068

Change in BW, lb 7 14 26 41 42 2 15 24 16.2

Ending Cow BCS 5.13 5.15 5.18 5.30 5.24 5.19 5.24 5.17 0.081

Ending Cow BW, lb 1106 1172 1136 1188 1179 1151 1167 1183 21.1

aBody condition scale: 1 = extremely emaciated; 9 = extremely obese.bContrasts for supplementation level across fall supplementation treatments were linear and cubic(P<0.05).cContrasts for supplementation level across fall supplementation treatments were cubic (P<0.05).

Table 4. Effect of Fall Supplementation on Pregnancy Rate of Beef Cows GrazingTallgrass-Prairie Forage

Treatment

ItemNo Fall

SupplementationFall

Supplementation Chi-Square (Pa)

No. of Cows 74 74

Pregnancy Rate, % 96 92 0.31aProbability of a greater F-value.

Table 5. Effect of Winter Supplementation Level on Pregnancy Rate of Beef CowsGrazing Tallgrass-Prairie Forage

Winter Supplement lb cube/head/day

Item 1 2 3 4 Chi-Square (Pa)

No. of Cows 35 38 37 38

Pregnancy Rate, % 86 95 97 97 0.04aProbability of a greater F-value.


42


ESCHERICHIA COLI O157:H7 RISK ASSESSMENTFOR PRODUCTION AND COOKING OF

RESTRUCTURED BEEF STEAKS

M. T. Ortega-Valenzuela, R. K. Phebus, H. Thippareddi,J. L. Marsden, and C. L. Kastner

Summary

Distribution of Escherichia coli O157:H7in restructured beef from artificially inocu-lated meat pieces and destruction of E. coliO157:H7 in restructured beef steaks preparedfrom artificially inoculated meat was evalu-ated following broiling and grilling. InStudy I, longissimus dorsi trimmings wereinoculated with fluorescently marked E. coliO157:H7 cells to microscopically identifybacterial distribution throughout restructuredsteak cross-sections. E. coli O157:H7 fluo-rescent density was observed along the gluelines where meat pieces were enzymaticallyattached. Study II quantified the level of E.coli O157:H7 throughout the entire thicknessof restructured beef. Cross-sectional slices ofcore samples from the steaks showed thatbacterial contamination was evenly distrib-uted (ca. 106 CFU/g). Study III determinedthe extent of E. coli O157:H7 reductionachieved during cooking. Beef trimmingswere inoculated to a level of 107 CFU/g andused to prepare restructured beef chubs.Restructured steaks of three thicknesses (0.5,1.0, and 1.5 inches) were sliced from thechubs and cooked to one of six target inter-nal temperatures (120, 130, 140, 150, 160, or170°F) by commercial gas grill or ovenbroiler. Broiling was more effective thangrilling, although E. coli O157:H7 survivaldecreased as endpoint temperaturesincreased incrementally. To achieve anadequate level of safety confidence, restruc-tured steaks should be cooked in a mannersimilar to ground beef; to an internal temper-ature of at least 160°F.

(Key Words: E. coli O157:H7, RestructuredBeef Steaks, Cooking.)

Introduction

Meat restructuring using cold set bindingtechnologies like fibrinogen and thrombinenzymes provide quality, economic, nutri-tional, and marketing advantages in meatprocessing. Food poisoning outbreaks withEscherichia coli O157:H7 have frequentlybeen attributed to ground beef consumedafter cooking that was insufficient to destroypathogens that were translocated from thesurface to the meat interior. Restructuredsteaks may be perceived as more like intactmuscle steaks than as ground beef. Becauseof this perception, restructured steaks may becooked at temperatures inadequate to destroysurface microbial contamination that mayhave been carried to the interior of therestructured product. The objectives of ourresearch were to determine the extent of E.coli O157:H7 translocation in restructuredbeef and to determine adequate cookingprotocols to eliminate E. coli O157:H7 fromtheir interior.


Study I:Five strains of Escherichia coli O157:H7

(USDA-FSIS 011-82, ATCC 43888, 43889,43890, and Eh 7-4) were grown and markedusing a fluorescent probe, live-cell nucleicacid stain. Longissimus dorsi beef trimmingswere mist inoculated (ca. 7 log10 CFU/g) andallowed to attach at 39°F for 1 hr. Thawedproportional parts of fibrinogen andthrombin enzymes, were mixed with thelongissimus dorsi trimmings for 90 sec andstuffed into perforated casings using anAligned Grain System™. The formed meatwas hung at 41°F for 10 hr for setting themeat pieces, and frozen for 1.5 hr to form a


43

surface crust to facilitate sample collection.A sterile stainless steel coring device cou-pled to an electric drill was used to core thesample along the width of the cylindricalmeat piece. The cores were fixed in a mix-ture of paraformaldehyde (2%) andglutaraldehyde (0.2%) in neutral buffersolution (pH 7) for 6 hr, sectioned and visu-alized under a confocal laser microscope.

Study II:A strain of E. coli O157:H7 (USDA-

FSIS 011-82, rifampcin resistant) was mistinoculated (ca. 7 log10 CFU/g) onto thesurface of longissimus dorsi beef trimmings.The restructuring procedure from Study Iwas followed. The formed beef roll (crustfrozen) was sampled as previously describedat three different locations about 4 inchesapart. The meat cores were aseptically slicedinto cross-sectional strips of 0.8, 0.4, 0.4,0.4, and 0.8 inches. Each cross-sectionalstrip was plated onto TSA-rif and the E. coliO157:H7 population was reported.

Study III:The inoculation and restructuring proce-

dures from Study I were followed. Thecylindrical restructured beef chub (2.8" inchdiameter) was sliced into steaks of 0.5, 1.0,and 1.5 inch thickness. Steaks were ran-domly assigned to six target internal temper-ature groups (120, 130, 140, 150, 160, and170°F) and were cooked under a typicalkitchen oven broiling element set at 500°F,or cooked using a commercial gas grill.Steaks were flipped upon reaching the mid-point between original and final temperature.Internal temperatures were constantly moni-tored using a type T thermocouple threadedthrough the steak edge to the steak’s geomet-ric center. After reaching the target internaltemperature, steaks were removed from thegrill or broiler, placed in heat resistant bagsand immersed in an ice bath. Steaks wereblended in a sterile food processor and a 25g sample stomached in peptone water toprovide a 1:5 w/v dilution. Surviving E. coliO157:H7 populations were enumerated onMacConkey Sorbitol Agar (MSA) and Phe-nol Red Sorbitol Agar (PRSA). PRSA agarprovided an estimate of the level of ther-mally injured cells that may not have beendetected on MSA agar. Samples testing

negative by direct plating were qualitativelyevaluated following a modified USDAmethod. Presumptive E. coli O157:H7colonies were confirmed biochemically andserologically. Three replications were per-formed for each study.


Study I:Confocal laser scanning microscopy

revealed a high level of E. coli O157:H7contamination along cross-sections of therestructured beef chub. The fluorescentbacteria present midway through the cylin-drical restructured meat piece shows that therestructuring process translocates surfacecontamination into the interior.

Study II:E. coli O157:H7 was uniformly distrib-

uted (P>0.05) across the diameter (5 individ-ual cross sections) of the restructured beefchub, indicating translocation of surfaceinoculated E. coli O157:H7 into the interiorof the chubs during restructuring. Section 3,corresponding to the geometric center of thecore, revealed a mean bacterial population of6.16 log10 CFU/g. This section would be thecoldest point during cooking.

Study III:Broiling steaks from restructured beef

trimmings to endpoint temperatures of 120,130, 140, 150, 160, and 170°F resulted in E.coli O157:H7 reductions of 1.03, 1.94, 2.70,4.32, 6.27, and 6.08 log CFU/g, respectively,when plated on PRSA (1 log = 90%, 4 log =99.99% reduction). Greater reductions wereobtained when a selective medium (MSA)was used for plating, indicating sub-lethalinjury to E. coli O157:H7 cells during cook-ing. Cooking of thicker steaks (1.0 and 1.5inches) resulted in consistently larger reduc-tions in E. coli O157:H7 compared to the 0.5inch steaks. This probably was due tothicker steaks requiring longer cookingtimes. The post-cook temperature rise washigher for 1.5-inch thick steaks (9 to 22°F)compared to steaks 1.0 and 0.5 inch thick (3to 8°F and 7 to 12°F for 0.5 and 1.0 inchthick steaks, respectively). The additionalmicrobial destruction in thicker steaks due tolonger cook times and higher post-cook


44

temperature rise results in a safer steak,compared to thinner steaks.

Cooking restructured steaks on a gas grillto endpoint temperatures of 120, 130, 140,150, 160, and 170°F resulted in E. coliO157:H7 reductions of 0.87, 1.16, 1.25,2.62, 3.73, and 4.51 log CFU/g, respectively,when plated on PRSA. These reductionswere greater when a selective medium(MSA) was used for plating the samples,indicating a significant number of injured butnot killed E. coli O157:H7 cells. Thesereductions were lower than the reductionsattained using oven broiling. This was prob-ably due to the commercial grill using highertemperatures and shorter cooking times toreach target temperatures.

Initial studies indicated that some re-structured steaks curled during cooking,probably due to different fiber alignmentthan normal steaks. Use of cook weights (1lb steel plates with a handle) minimized butdid not eliminate the curling. Using commer-cial grill systems can result in cold spots onsteaks due to curling, and thus reduce micro-bial destruction. In addition, when cookedon a grill, the top surface of the steak isexposed to near ambient temperatures. On thecontrary, in oven broiling, the temperature is more

consistent and uniform because steaks areheated from the top (broiling element). Thesurface of the holding grill is close to theoven temperature, resulting in larger reduc-tions in E. coli O157:H7 populations.

Grilling thicker steaks (1.0 and 1.5inches) resulted in larger reductions of E.coli O157:H7 compared 0.5 inch thicksteaks, probably due to the longer cooktimes and higher post-cook temperature rise.As observed in oven broiling, the post-cooktemperature rise was greater in steaks of 1.0and 1.5 inches (1 to 16°F and 6 to 19°F).

This study incorporated the use of an icebath to rapidly halt destruction of bacteriaafter steaks were removed from the broiler,to provide more accurate information con-cerning microbial destruction achieved at theidentified target internal temperatures.However, even after transfer to the ice bath,internal temperature of the steaks continuedto rise above the target temperatures by asmuch as 4 to 29°F. In food service applica-tions, the finished product would not becooled. Therefore, internal temperatureswould likely rise to higher endpoints and bemaintained longer, thereby increasing marginof safety in pathogen destruction.


45


TEMPERATURE ACCURACY OF AN ELECTRICBELT GRILL, A FORCED-AIR CONVECTION

OVEN, AND AN ELECTRIC BROILER

T. E. Lawrence, D. A. King, and M. E. Dikeman

Summary

We evaluated the temperature variationof an electric belt grill set at four tempera-tures, a forced-air convection oven set atthree temperatures, and an electric broilerthat has no temperature control. After find-ing that the actual temperatures of the elec-tric belt grill and the forced-air convectionoven were higher than the targeted tempera-ture, we used regression techniques to cor-rect for the temperature biases of both cook-ing methods. The forced-air convectionoven was very precise when the doors werekept closed, as was the electric belt grill afteradjustments were made. Temperature of theelectric broiler was not consistent acrosssurface positions or among replications. Wesuggest that when used for cooking experi-ments, each meat-cooking instrument bevalidated for temperature and corrected whennecessary. This will improve cooking con-sistency and related results among variousinstruments and research institutions.

(Key Words: Cooking, Temperature, Meth-ods, Meat.)

Introduction

Many researchers consider actual oventemperatures to be constant with the thermo-stat settings, with little or no variation.Cooking methods used for research shouldachieve the desired target temperature andmaintain that temperature for the duration ofthe cooking process so that measures such ascooking loss and shear force values will bereliable and repeatable. Cooking methodsfor research have often utilized electricbroilers, forced-air convection ovens, ormore recently, electric belt grills. We evalu-

ated the temperature variation and accuracyof a single example of each of these instru-ments.


We monitored the temperature at 18locations (9 for each platen) on an electricbelt grill (TBG-60 Magigrill, MagiKitch'nInc., Quakertown, PA) set at 160, 242, 325,and 408°F; 18 locations in a forced-air con-vection oven (Blodgett, model DFG-102CH3, G.S. Blodgett Co., Burlington, VT) setat 225, 325, and 425°F; and 12 locations onan electric broiler (Open Hearth electricbroiler, Farberware, Yonkers, NY). Theelectric belt grill cooks by moving a productbetween two heated platens using conveyorbelts. In this conduction type of heating, aproduct is heated from the top and bottomsimultaneously. Unloaded temperature ofeach oven was monitored using copper-constantan thermocouples (Omega Engineer-ing, Stamford, CT) connected to a Dorictemperature recorder (Vas Engineering, SanFrancisco, CA). The electric belt grill andforced-air convection oven were monitoredfor two replications, and the electric broilerwas monitored for three. Linear regressionanalysis was used to correct for temperaturebias in the electric belt grill and forced-airconvection oven.


The electric belt grill was 8, 13, 20, and26°F high when set at 160, 242, 325 and408°F, respectively. The forced-air convec-tion oven produced temperatures 5, 4.5, and1.4°F higher than it was supposed to at set-tings of 225, 325, and 425°F. Linear regres-sion equations developed to correct for the


46

temperature bias of the electric belt grill andforced-air convection cooking methods arereported in Table 1. Based on the regressionequations, the set points of the electric beltgrill and forced-air convection oven wereadjusted to obtain the desired temperatures.Results before and after adjustment areshown in Table 2 for the electric belt grilland Table 3 for the forced-air convectionoven. Temperature variation from point topoint was relatively high for the electric beltgrill (Table 2) but was small for the forced-

air convection oven (Table 3). The electricbroiler had a mean operating temperature of245.1°F; but varied from 194.4°F to 292.8°Fdepending upon location. These data empha-size that temperature for each cooking instru-ment used for research should be validatedand corrected when necessary. These qualitycontrol measures will assure accurate report-ing of procedures and reduce variation incooking and related results (cooking loss,shear force value) among instruments andresearch institutions.

Table 1. Linear Regression Equations to Correct for Temperature Bias of CookingMethods

Cooking Method Intercept Slope R2 P > FElectric belt grill (top platen) 4.523 .932 .99 .001Electric belt grill (bottom platen) 6.050 .921 .99 .001Forced-air convection oven 10.342 .979 .99 .001

Table 2. Mean Top and Bottom Electric Belt Grill Platen Temperatures Before andAfter Temperature Adjustment (°F)

TargetedTemperature

TopPlaten

Unadjusted

BottomPlaten

UnadjustedRange

Unadjusted

TopPlaten

Adjusted

BottomPlaten

AdjustedRange

Adjusted

160°F 168.3 168.3 164.4-171.1 160.0 160.5 156.3-163.9242°F 254.3 256.5 247.1-263.5 243.9 245.5 236.3-252.2

325°F 343.4 346.1 332.0-356.9 325.9 326.7 312.1-334.7408°F 432.7 435.7 419.2-451.8 410.2 410.5 396.1-425.1

Table 3. Mean Temperature Before and After Temperature Adjustment for theForced-Air Convection Oven (°F)

Targeted temperature Unadjusted Range Adjusted Range

225°F 219.9 219.3-220.7 225.0 222.9-225.8325°F 320.4 320.2-323.0 324.9 323.3-326.3

425°F 423.9 422.2-426.3 425.3 423.6-427.2


47


TENDERNESS AND COOKING CHARACTERISTICS OF BEEFCOOKED BY ELECTRIC BELT GRILL, FORCED-AIR

CONVECTION OVEN, OR ELECTRIC BROILER

T. E. Lawrence, D. A. King, E. Obuz,E. J. Yancey, and M. E. Dikeman

Summary

We used an electric belt grill, a forced-airconvection oven, and an electric broiler tocook 170 bottom round, 142 brisket, 177 topsirloin, 176 strip loin, and 136 eye of roundsteaks from USDA Select carcasses to deter-mine the effects of cooking method andmuscle on shear force values, cooking traits,and repeatability of duplicate measurements.All cooking treatments allowed differencesto be detected (P<0.05) in Warner-Bratzlershear force, although the differences wereinconsistent. Shear force values of stripsteaks and eye of round steaks were similaracross cooking treatments; however, shearforce values of bottom round, brisket, andtop sirloin steaks were different (P<0.05)among cooking treatments. Based on poorrepeatability, shear force values for topsirloin steaks appear unreliable. Poor repeat-ability for shear force values from steakscooked by the forced-air convection oven area result of drastic temperature changes thatoccur when the doors are opened to removesteaks. We do not recommend using aforced-air convection oven to test treatmenteffects on shear force values when cookingmultiple steaks simultaneously. Belt grillcooking resulted in the highest shear forcerepeatability R = 0.07 to 0.89) of strip steaks.Electric broiling resulted in acceptable R =0.60) repeatability of shear force measure-ments for all classes of steaks. The electricbroiler and electric belt grill are both satis-factory cooking methods when measuringshear force of bottom round, brisket, striploin, and eye of round steaks.

(Key Words: Beef, Cooking, Repeatability,Tenderness.)

Introduction

Cooking method is one of the most im-portant factors influencing the tenderness ofbeef. Cooking methods used for researchshould give highly repeatable results; andshould neither mask nor enhance treatmenteffects. Previous research has suggested theuse of an electric belt grill instead of anelectric broiler for steak tenderness research,based on increased precision and repeatabil-ity of duplicate measurements. Other re-search has suggested not using forced-airconvection cooking because of inconsistentcooked product characteristics. Our objec-tives were: (1) to determine if differences inWarner-Bratzler shear force (WBSF) can bedetected among steaks from five musclescooked on an electric belt grill, in a forced-air convection oven, or on an electric broiler;and (2) to determine the repeatability ofWBSF values and cooking traits.


We cut one-inch thick steaks from 18briskets (NAMP 120), 18 top sirloin butts(NAMP 184), 18 loin strips (NAMP 180), 17bottom rounds (NAMP 170), and 17 eye ofrounds (NAMP 170) from USDA Selectcarcasses. Identification of subprimal andsteak location within subprimal were main-tained. All steaks were aged 14 days at 34°F.Consecutive pairs of steaks were randomlyassigned to one of five cooking treatments:electric belt grill (TBG-60 Magigrill,MagiKitch'n Inc., Quakertown, PA) at 200,242, or 325°F; forced-air convection oven(Blodgett, model DFG-102 CH3, G.S.Blodgett Co., Burlington, VT) at 325°F; orelectric broiler (Open Hearth electric broiler,Farberware, Yonkers, NY). The electricbroiler had no temperature control. All


48

steaks were cooked to an internal tempera-ture of 158°F and then removed from thecooking device. Total cooking loss, cookingtime, and endpoint temperature (maximumtemperature reached after removal from thecooking device) of each steak was recorded.After cooking, steaks were refrigeratedovernight (39°F). We removed six roundcores (1/2 inch in diameter) parallel to themuscle fiber direction and sheared each oneonce through the center with a V-shapedWBSF attachment on an Instron UniversalTesting Machine. We analyzed the data bytwo-way analysis of variance with five levelsof each factor. Our model included the fixedeffects of muscle, cooking treatment, andmuscle × cooking treatment interaction aswell as the random effects of subprimal,steak location within subprimal, and replica-tion. Muscle × cooking treatment interactionmeans were generated and separated whensignificant (P<0.05). Repeatability for con-secutive steaks within cooking treatmentswas calculated as follows: (variance ofsubprimal + variance of steak location withinsubprimal) ÷ (variance of subprimal + vari-ance of steak location within subprimal +error variance).


All cooking treatments allowed detectionof differences (P<0.05) in WBSF valuesacross the five muscles (Table 1); howeverdifferences were inconsistent. Bottom roundand eye of round steaks had similar WBSFvalues when cooked by the belt grill at200°F, the forced-air convection oven, or theelectric broiler; however, bottom roundsteaks were tougher (P<0.05) than eye ofround steaks when cooked on the belt grill at325°F. Top sirloin steaks were tougher(P<0.05) than strip steaks when cooked inthe forced-air convection oven; however,they were similar for all other cooking treat-ments. Top sirloin steaks were more tender(P<0.05) than eye of round steaks for allcooking treatments except for the belt grill at325°F.

Endpoint temperatures were similar forall muscles within a cooking treatment (Ta-ble 2). Cooking loss was higher (P<0.05) foreye of round steaks than for all other muscles

when cooked by the belt grill at 200°F or theforced-air convection oven (Table 3). Cook-ing times were similar across the five mus-cles when cooked in the belt grill at anytemperature; however, differences (P<0.05)in cooking times were detected for theforced-air convection and electric broilercooking treatments (Table 4). In the forced-air convection oven, strip steaks cookedfaster (P<0.05) than bottom round and topsirloin steaks, which cooked faster (P<0.05)than eye of round steaks. In the electricbroiler, strip steaks cooked faster (P<0.05)than brisket steaks, which cooked faster(P<0.05) than bottom round or eye of roundsteaks.

WBSF values for bottom round, brisket,and top sirloin steaks were not consistent(P<0.05) across the five cooking treatments(Table 1); however, values for strip steaksand eye of round steaks were consistentacross all cooking treatments. Bottom roundsteaks were tougher (P<0.05) when cookedby the belt grill at 325°F than by any othercooking treatment. Brisket steaks weretougher (P<0.05) when cooked by the elec-tric broiler than when cooked by the belt grillat 200 or 242°F. Top sirloin steaks weretougher (P<0.05) when cooked by the forced-air convection oven than when cooked by thebelt grill at 200°F.

Belt grill cooking at 325°F resulted in thehighest post-cooking temperature rise for allfive muscles, which were higher than for thebelt grill at 200°F, the forced-air convectionoven, or the electric broiler (Table 2). Elec-tric broiling did not result in a significantpost-cooking temperature rise, whereas thebelt grill at 325°F resulted in a consistent 7°Fpost-cooking temperature rise for all mus-cles. Cooking losses for bottom round,brisket, top sirloin, and strip steaks tended tobe higher for the electric broiler treatmentthan any other (Table 3), while the lowest(P<0.05) cooking losses resulted from beltgrill cooking at 200°F. Cooking time waslongest for the electric broiler followed bythe forced-air convection oven and belt grillcooking at 200, 242, and 325°F, respectively(Table 4).


49

Repeatability of shear force values wasacceptable (repeatability ≥ 0.60) for bottomround and eye of round steaks cooked by alltreatments (Table 5). Strip steak repeatabil-ity was highest when cooked by the belt grillat 242 or 325°F and unacceptable for theforced-air convection oven. Only the electricbroiler provided acceptable repeatability fortop sirloin steaks. Repeatability was unac-ceptable for brisket steaks cooked by the beltgrill at 242°F. The electric broiler was theonly cooking method that provided accept-able shear force repeatability for all muscles.The forced-air convection oven providedpoor shear force repeatability, which can bestbe explained by the drastic temperaturechanges that occur when the oven is openedto remove steaks. Endpoint temperature

repeatability was not acceptable for any steakcooked by any treatment (Table 5). Cookingtime repeatability was acceptable only forbottom round steaks cooked in the forced-airconvection oven and top sirloin steakscooked by the belt grill at 242°F. Cookingtime range was 3.7 minutes for bottomround, 7.4 for brisket, 5.8 for top sirloin, 3.8for strip, and 7.0 for eye of round steaks.Repeatability of cooking losses was accept-able only for brisket steaks cooked by thebelt grill at 200°F, top sirloin cooked by thebelt grill at 242°F or electric broiler, and eyeof round steaks cooked in the forced-airconvection oven. Endpoint temperature,cooking time and cooking loss repeatabilitiesare important because variations in each canaffect repeatability and reliability in WBSF.

Table 1. Warner-Bratzler Shear Force Measurements (Least Squares Means, lb) ofSteaks from Five Muscles and Five Cooking Treatments

CookingTreatment

BottomRound Brisket

Top Sirloin Strip

Eye ofRound

Belt grill (200°F) 10.21r,w 13.51q,x 8.29s,w 8.31s 9.57r

Belt grill (242°F) 10.32r,w 14.02q,w,x 8.38s,v,w 8.07s -Belt grill (325°F) 11.84r,v 14.99q,v,w 9.17s,t,v,w 8.55t 9.81s

Forced-air convection (325°F) 10.25q,r,v - 9.35r,v 8.20s 10.56q

Electric broiler 10.78r,v 15.92q,v 8.62s,v,w 8.33s 10.47r

n = 32-36 per cell.q,r,s,tWithin a row, means lacking a common superscript letter differ (P<0.05).v,w,xWithin a column, means lacking a common superscript letter differ (P<0.05).

Table 2. Endpoint Temperature (Least Squares Means, °F) of Steaks from FiveMuscles and Five Cooking Treatments*

CookingTreatment

BottomRound Brisket

Top Sirloin Strip

Eye ofRound

Belt grill (200°F) 161.3w 160.5w 161.3x 161.3w 161.9w

Belt grill (242°F) 164.1v 164.6v 165.8 v,w 165.3v -Belt grill (325°F) 165.7v 166.2v 166.1v 166.1v 166.8v

Forced-air convection (325°F) 160.7w - 161.7w,x 160.2w,x 160.6w,x

Electric broiler 158.8x 159.8w 159.4y 159.2x 159.1x

n = 32-36 per cellv,w,x,yWithin a column, means lacking a common superscript letter differ (P<0.05).*No muscle differences were found within a cooking method.


50

Table 3. Percentage Cooking Loss (Least Squares Means) of Steaks from Five Musclesand Five Cooking Treatments

CookingTreatment

BottomRound Brisket

Top Sirloin Strip

Eye ofRound

Belt grill (200°F) 19.86r,x 20.78r,x 20.98r,x 21.54r,w 25.34q,x

Belt grill (325°F) 27.42 q,r,w 26.49r,w 27.08q,r,w 26.17r,v 28.69q,w

Forced-air convection (325°F) 28.03r,w - 29.63r,v 25.89s,v 33.40q,v

Electric broiler 30.63q,v 30.18q,v 30.63q,v 27.60r,v 31.66q,v

n = 32-36 per cell*Cooking loss of the Belt grill (242°F) was excluded due to a mechanical malfunction.q,r,sWithin a row, means lacking a common superscript letter differ (P<0.05).v,w,xWithin a column, means lacking a common superscript letter differ (P<0.05).

Table 4. Cooking Time (Least Squares Means, Minutes) of Steaks from Five Musclesand Five Cooking Treatments

CookingTreatment

Bottom Round Brisket

TopSirloin Strip

Eye ofRound

Belt grill (200°F) 10.64x 10.53w 10.48w 10.87x 10.80w

Belt grill (242°F) 8.33y 7.45x 7.64x 8.04y -

Belt grill (325°F) 7.13y 6.40x 6.72x 6.93y 6.67x

Forced-air convection (325°F) 25.32r,w - 26.44r,v 21.09s,w 32.80q,v

Electric broiler 31.78q,v 26.28r,v 26.07r,s,v 25.23s,v 31.33q,v

n = 32-36 per cellq,r,s Within a row, means lacking a common superscript letter differ (P<0.05).v,w,x,y Within a column, means lacking a common superscript letter differ (P<0.05).


51

Table 5. Repeatability of Warner-Bratzler Shear Force Measurements and CookingTraits

VariableBelt Grill(200°F)

Belt Grill(242°F)*

Belt Grill(325°)

Forced-AirConvection

(325°F)ElectricBroiler

Bottom RoundEndpoint temperature (°F) 0.44 0.00 0.00 0.00 0.38Cooking loss (%) 0.37 - 0.16 0.37 0.38Cooking time (min) 0.36 0.06 0.00 0.67 0.39Shear force (lbs) 0.79 0.66 0.83 0.87 0.89

BrisketEndpoint temperature (°F) 0.41 0.13 0.26 - 0.08Cooking loss (%) 0.77 - 0.43 - 0.31Cooking time (min) 0.01 0.16 0.00 - 0.18Shear force (lbs) 0.62 0.55 0.76 - 0.68

Top SirloinEndpoint temperature (°F) 0.39 0.26 0.18 0.21 0.00Cooking loss (%) 0.38 - 0.00 0.14 0.70Cooking time (min) 0.56 0.71 0.00 0.18 0.53Shear force (lbs) 0.35 0.58 0.09 0.09 0.66

StripEndpoint temperature (°F) 0.00 0.10 0.05 0.27 0.30Cooking loss (%) 0.07 - 0.12 0.13 0.44Cooking time (min) 0.06 0.51 0.35 0.08 0.19Shear force (lbs) 0.70 0.89 0.83 0.50 0.63

Eye of RoundEndpoint temperature (°F) 0.45 - 0.04 .030 0.00Cooking loss (%) 0.48 - 0.24 0.60 0.40Cooking time (min) 0.26 - 0.04 0.34 0.04Shear force (lbs) 0.83 - 0.86 0.79 0.67

n = 32-36 per cell *Cooking loss excluded due to a mechanical malfunction.


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HEAT PENETRATION PATTERNS OF OUTSIDE ROUND,LOIN STRIP AND EYE ROUND MUSCLES COOKED BY

ELECTRIC BROILER, ELECTRIC BELT GRILL, ORFORCED-AIR CONVECTION OVEN

E. Obuz, E. J. Yancey, T. E. Lawrence,D. A. King, and M. E. Dikeman

Summary

We used an electric belt grill, a forced airconvection oven, and an electric broiler tocook steaks from three beef muscles; outsideround (biceps femoris), loin strip (longissimuslumborum) and eye round (semitendinosus).Belt grill cookery gave the fastest heat penetra-tion into steaks regardless of temperatureinterval. Eye round had the slowest heat trans-fer rate for each cooking method perhapspartially explained by its fiber orientation.Heat penetration rate into outside round andloin strip was not different (P>0.05) for cook-ing method within a given temperature range.Heat penetration into muscles between 140 and158°F was slowest because energy-expensivereactions (collagen and protein denaturation)occur in that temperature and temperaturedifferential between the heat source and meatis less. Heat penetration also was slow between122 and 140°F due to the denaturation ofcontractile proteins.

(Key Words: Heat Penetration, Belt Grill,Forced-Air Convection Oven, ElectricBroiler.)

Introduction

Heat penetration into meat is affected bymany factors. The energy supply rate, heatconduction within the meat, shape and size ofthe meat, meat composition, changes inducedin meat by heat, for example, protein andcollagen denaturation and melting of fat affectheat penetration. Heat penetration is fasterwhen heat is applied parallel to product fibers.The rate of heat penetration is generally mostrapid between 50 and 104°F because energy-expensive processes such as protein denatur-ation have not occurred. On the other hand,

heating rate between 140 and 158°F is theslowest due to collagen and protein denatur-ation and a smaller temperature differentialbetween the heat source and meat. Contactcooking equipment such as a belt grill shouldresult in the fastest heat penetration becauseof its very high heat transfer coefficient. Theheat loss from the open surface of an electricbroiler causes heat transfer into meat to beslower than contact cooking. Forced-airconvection ovens give effective but slowheat penetration. Air has low thermal con-ductivity, so heat transfer between air andmeat product in a forced-air convection ovenis slower than in a belt grill.


We purchased USDA Select subprimals[(beef strip loin, boneless (NAMP 180) andbeef round, bottom (gooseneck) (NAMP170)] (n=17 or 18 each) and removed outsideround (biceps femoris, BF, n=17), loin strip(longissimus lumborum, LL, n=18), and eyeround (semitendinosus, ST, n=17). Muscleswere vacuum packaged and held at 34°F for14 days, then frozen and stored at -35°F.

Frozen muscles were sawed into 1-inchthick steaks, which were vacuum packagedand stored. We thawed steaks at 39°F for 24hours before cooking and cooked them byone of three cooking methods: electric beltgrill at 325°F, forced-air convection oven at325°F, or electric broiler (no temperaturecontrol). We cooked all steaks to the end-point temperature of 158°F. The centertemperature of steaks was monitored usingcopper-constantan thermocouples. Tempera-ture was recorded and heat penetration ratefor each muscle was calculated asminutes/°F.


Results were analyzed in a completely Heat penetration for eye round muscle be-randomized design using the General Linear tween 50 and 68°F was almost three timesModel procedure (SAS, 1998). faster than between 140 and 158°F, when

Results and Discussioncooked by either forced-air convection ovenor electric broiler. Although loin strip andoutside round showed the same trend both

Belt grill cookery gave the fastest heat required less heat between 140 and 158°Fpenetration rate for muscles studied (Table 1). than eye round. Belt grill cookery resulted inForced air convection oven and electric broiler no differences in heat transfer rate due togave similar results in most cases. Heat pene-tration rate into any given muscle decreased

muscle in any temperature interval studied

above 104°F since denaturation of contractilebecause heat transfer was very fast.

proteins, which starts at about 104°F, leads to Different heat penetration rates for theslower heat penetration. The slowest heating three muscles may be explained by differ-rates occurred in the 140-l 58°F interval, fol- ences in fat, collagen water, and elastinlowed by 122-140°F interval. At all tempera-ture intervals, eye round required more energy.

content and fiber orientation.

Steaks enter the belt grill on the right and exit on the left. During operation the distancebetween the two belts is adjusted so that the hot belts touch both the top andand bottom ofthe steaks.


IET n/a

53

54

Table 1. Heat Penetration (min/°F) Cooking Treatment × Muscle Interaction Means

50 to 68°F

Cooking Method

Muscle Belt grill Forced-air convection oven Electric broiler

BF 0.04a,x 0.13b,x 0.12b,x

LL 0.04a,x 0.14b,x 0.15c,x

ST 0.04a,x 0.16b,y 0.16b,y

68 to 86°F

Cooking Method


BF 0.04a,x 0.13b,x 0.12b,x

LL 0.04a,x 0.12b,x 0.14c,x

ST 0.04a,x 0.17b,y 0.17b,y

86 to 104 °F

Cooking Method


BF 0.04a,x 0.17b,x 0.19b,x

LL 0.04a,x 0.15b,x 0.13b,y

ST 0.04a,x 0.22b,y 0.17c,xy

104 to 122°F

Cooking Method


BF 0.04a,x 0.21b,x,y 0.16b,x

LL 0.04a,x 0.18c,x 0.13b,x

ST 0.04a,x 0.26b,y 0.25b,y

122 to 140°F

Cooking Method


BF 0.05a,x 0.23b,x 0.26b,y

LL 0.06a,x 0.22c,x 0.18b,x

ST 0.05a,x 0.32b,y 0.33b,z

140 to 158°F

Cooking Method


BF 0.07a,x 0.33b,x 0.38b,y

LL 0.07a,x 0.37b,x 0.31b,x

ST 0.07a,x 0.46b,y 0.47b

a,b,cWithin a row, means lacking a common superscript letter differ (P<0.05).x,y,zWithin a column, means lacking a common superscript letter differ (P<0.05).


55


THE EFFECTS OF QUALITY GRADE, POSTMORTEMAGING, AND BLADE TENDERIZATION ON WARNER-BRATZLER SHEAR FORCE AND

COOKERY TRAITS OF BICEPS FEMORIS STEAKS

B. S. Andrews and J. A. Unruh

Summary

We used 108 top sirloin butts to deter-mine the influence of quality grades, post-mortem aging periods, and blade tenderizati-on passes on percentages of thawing andcooking losses and Warner-Bratzler shear(WBS) force of biceps femoris muscles. Topsirloin butts that qualified for either USDASelect (SEL, n=36), USDA Choice (CHO,n=36), or Certified Angus Beef™ Program(CAB, n=36), were aged for 14 or 21 daysand blade tenderized zero (0X), one (1X), ortwo (2X) times. Steaks with higher qualitygrades (CHO and CAB) aged for 21 days hadlower thawing losses than steaks aged 14days and than SEL steaks aged for 21 days.Steaks aged for 14 days and not blade ten-derized (0X) had higher thawing losses thansteaks aged for longer periods (21 days) andtenderized 0X, 1X, and 2X. Lower qualitygrade steaks (SEL) blade-tenderized 2X hadlonger cooking times than other qualitygrade×blade tenderization treatments. Moreblade tenderization passes (1X and 2X) forhigher quality grades (CHO and CAB) ap-pear to lower WBS values. The most tendertreatments were CHO steaks blade tender-ized 2X and CAB steaks blade tenderized 1Xand 2X. Biceps femoris tenderness wasinconsistent among all treatments, althoughaging, blade tenderization, and higher qualitygrades reduce variation. For reliable, accept-able quality this muscle should not be in-cluded in top sirloin butt steaks.

(Key Words: Quality, Blade Tenderization,Postmortem Aging, Biceps femoris, Tender-ness.)

Introduction

Consumers are willing to pay a premiumfor cuts of meat they know are tender. Ofsteaks offered in a restaurant setting, thosefrom the top sirloin butt are among the morevariable, less tender cuts. To help alleviatethis problem and decrease variation in ten-derness, the cap (biceps femoris, BF) mus-cles are removed from the top sirloin buttsprior to fabrication into steaks. The BF isconsidered highly variable in tenderness andis a tougher muscle, which reduces the eatingsatisfaction of sirloin steaks, compared to themain muscle of the top sirloin butt, (gluteusmedius, GM). Postmortem technologiessuch as aging and blade tenderization canimprove tenderness uniformity and overallacceptability of the BF. This might allow theBF to remain on the top sirloin during fabri-cation into steaks. Our objective was todetermine the influence of quality grades,postmortem aging, and blade tenderizationpasses on tenderness of BF muscle.


One hundred eight top sirloin butts(IMPS 184A) that qualified for either theCertified Angus Beef™ Program (CAB;n=36), USDA Choice (CHO; n=36), orUSDA Select (SEL; n=36) were tested. Topsirloin butts were sent to a commercial fabri-cation plant and aged for 14 or 21 dayspostmortem at 32°F. After aging, they wereeither not blade tenderized (0X) or passedthrough a blade tenderizer (Model T7001,Ross Industries Inc., Midland, VA) one (1X)or two (2X) times. The BF muscle was re-moved from each top sirloin butt, labeled foridentification, then individually vacuumpackaged (Model M860, Multivac Inc.,


56

Calhoun, Germany) and frozen for 40 min at-35°F in a spiral freezer. Once frozen, BFwere transported to Kansas State UniversityMeat Laboratory and stored at -29°C untilanalysis.

Each BF muscle was sawed into 1 inchthick steaks, weighed, and thawed at 37°Ffor 24 hours. Steaks were cooked to 160°Finternally by a Blodgett dual-air-flow gasconvection oven. Internal steak temperaturewas monitored by a 30-gauge, type-T ther-mocouple attached to a Doric 205 tempera-ture recorder. Steaks were allowed to coolovernight in a refrigerator at 37°F. Six, ½inch cores were taken parallel to the musclefibers and sheared perpendicular to the coreusing an Instron Universal Testing Machinewith a V-shaped blade on a Warner-BratzlerShear force (WBS) attachment. Percentthawing losses [(Frozen wt.!Thawed wt.)/Frozen wt.]×100 and percent cooking loss[(Thawed wt.-Cooked wt.)/ Thawed wt.]×10-0 were calculated. Results were analyzed ina 3×2×3 factorial design using the SASGeneral Linear Model procedure.


Steaks aged 14 and 21 days had similar(P>0.05) percentages of cooking loss, cook-ing times, and WBS values (Table 1). Nei-ther quality grade nor number of bladetenderization passes influenced cooking loss(P>0.05). However, both aging period ×quality grade and aging period × number ofblade tenderization passes interactions(P<0.05) were observed for percentage ofthawing losses (Table 2). Choice and CABsteaks aged 21 days had lower (P<0.05)thawing losses than SEL steaks aged 21 daysand all steaks aged 14 days regardless ofquality grades. Steaks aged 21 days andblade tenderized 0X and 2X had lower(P<0.05) thawing losses than steaks aged 14days and blade tenderized 0X and 2X, re-

spectively. Also, steaks aged 21 days andblade tenderized 1X had less (P<0.05) thaw-ing loss than steaks aged 14 days and bladetenderized 0X. Higher quality grades (CHOand CAB) combined with prolonged aging(21 days) resulted in lower thawing losses.Longer aging periods (21 days) resulted inless thawing loss for steaks blade tenderizedfor 0X or 2X.

A quality grade × blade tenderizationpass interaction (P<0.05) was observed forcooking time and WBS values. Select steaksblade tenderized 2X had the longest (P<0.05)cooking times, while CAB steaks tenderized1X cooked in the shortest time (P<0.05).Blade tenderizing improved (P<0.05) WBSof CHO and CAB steaks but not SEL steaks(P>0.05). Choice steaks blade tenderized 2Xwere the most tender, while CAB steaks notblade tenderized were the toughest.

For foodservice, a WBS value of 8.6 lbs.or less has been used as a threshold for arating of at least “slightly tender.” All SELsteaks aged 21 days and blade tenderized 2Xand CAB steaks aged 21 days and bladetenderized 1X or 2X had WBS values below8.6 lbs (Table 3). All choice steaks aged 14days and blade tenderized 2X had WBSvalues below 8.6 lbs. While not conclusive,retailers could maximize the probability of“slightly tender” steaks by utilizing higherquality steaks, aged for at least 21 days, andblade tenderized 2X. Purveyors can usepostmortem aging and blade tenderizationtechnologies to increase the acceptability ofBF steaks. However, steaks from the BFwere tougher than steaks originating fromthe GM (KSU Cattleman’s Day, 2000) in alltreatments. Because postmortem aging andblade tenderization technologies fail toincrease the tenderness of the BF muscles toa level equal to the GM, removing the BF toreduce the variation in tenderness of topsirloin butt steaks is still recommended.


57

Table 1. Thawing Losses (TL), Cooking Losses (CL), Cooking Time (CT), andWarner-Bratzler Shear Force (WBS) Means of Biceps Femoris Steaks ofDifferent Quality Grades, Aging Periods, and Blade Tenderization Passes

USDAQuality Gradea

AgingPeriod

BladeTenderization

SEL CHO CAB 14 21 0X 1X 2X SETL, %b *d * * * * * * * *CL, % 30.4 29.1 28.6 29.9 29.8 30.2 28.2 29.7 0.67CT,c Min/100 g

*d * * 14.7 14.6 * * * 0.57WBS, kgc * * * 3.51 3.47 * * * 0.08aQuality Grades (SEL=Select, CHO=Choice, CAB=Certified Angus BeefTM); BladeTenderization (0X= Not blade tenderized, 1X=Blade tenderized one time, 2X=Bladetenderized two times).bQuality Grade × Postmortem Aging Period and Blade Tenderization Pass × PostmortemAging Period interactions.cQuality Grade ×Blade Tenderization Pass interaction.dInteraction means are presented on Table 2.

Table 2. Thawing Loss (TL), Cooking Time (CT), and Warner-Bratzler Shear Force(WBS) Means of Biceps Femoris Steaks as Affected by Interactions (P<0.05) ofQuality Grade, Aging Period, and Blade Tenderization Passesd

Quality Grade × Postmortem Aging PeriodSEL CHO CAB

14 days 21 days 14 days 21 days 14 days 21 days SETL, % 6.74b 6.70b 6.16b 4.87a 6.40b 4.69a 0.31

Postmortem Aging × Blade Tenderization Passes14 days 21 days

0X 1X 2X 0X 1X 2X SETL, % 7.10c 5.95abc 6.24bc 5.28a 5.70ab 5.27a 0.31

Quality Grade × Blade Tenderization PassesSEL CHO CAB

0X 1X 2X 0X 1X 2X 0X 1X 2X SECT,Min/100 g 14.13ab 15.10b 18.94c 15.06b 14.99b 12.27ab 13.00ab 11.48a 12.27ab 1.19WBS, kg 3.43bc 3.69bc 3.66bc 3.68bc 3.54bc 2.95a 3.84c 3.33ab 3.27ab 0.17a,b,cMeans within a row with different superscripts differ (P<0.05).dQuality Grades (SEL=Select, CHO=Choice, CAB=Certified Angus Beef™); Blade Tenderization(0X=not blade tenderized, 1X=blade tenderized one time, 2X=blade tenderized two times).


Table 3. Percent of “Slightly Tender” Steaks with Warner-Bratzler Shear Force(WBS) Values Below 8.6 Lbs

B l a d e Passesb 14c 21 21 21

ox 83d 83 50 50 67 33 22

1x 67 83 83 67 67 100 28

2 x 67 100 100 83 83 100 32

Total 72 72aSEL=Select, CHO=Choice, CAB=Certified Angus Beef Program*.bOX=Not blade tenderized, lX=Blade tenderized once, 2X=Blade tenderized twice.cAging perioddn=6 for each cell, total of 108 steaks is represented in this table.

During blade tenderization, meat is carried under the blades and the blades move up anddown, penetrating the meat. During a single pass, the blades make about 35 penetrationsper square inch.


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59


INFLUENCES OF AGING ON TENDERNESS ANDCOLOR OF BEEF STEAKS

R. R. Timm, J. A. Unruh, S. L. Stroda,K. A. Hachmeister, L. M. Sammel, and A. E. Rasor

Summary

Aging loin strip, bottom, and eye ofround steaks for 21 days decreased Warner-Bratzler Shear (WBS) values (increasedtenderness). For the top round, aged semi-membranosus muscle steaks tended to havelower WBS values (more tender) than non-aged steaks, while aged adductor steaks weresimilar to non-aged steaks. Furthermore,instrumental L* color values were higher(lighter) for aged strip and eye of roundsteaks than non-aged steaks, and instrumen-tal a* color values were higher (redder) foraged bottom round, eye of round, and topround (semimembranosus) steaks than non-aged steaks. Aging steaks is effective forimproving tenderness and color of strip,bottom, top (semimembranosus) and eye ofround steaks.

(Key Words: Aging, Beef, Color, Tender-ness.)

Introduction

Tenderness is a very important compo-nent of consumer satisfaction. Many factorsaffect tenderness such as breed type, animalage and sex, type of muscle, and cookingmethod. Aging requires storing meat atrefrigeration temperatures for varyinglengths of time. During aging, protein break-down contributes to tenderness. In a recentsurvey, 71% of North American Meat Pro-cessor members aged some product for anaverage of 20 days (7 to 60 days) to increasetenderness. Our objective was to examinethe effects of aging on tenderness and instru-mental color of loin strip, bottom round, eyeof round, and top round steaks.


We purchased USDA Select strip loins(longissimus dorsi; IMPS 180; n=30), toprounds (IMPS 169A; n=18), and goosenecks(IMPS 170; n=27) from a commercial pack-ing facility. Top and gooseneck rounds wererandomly selected; however, strip loins werepre-selected for toughness. Top rounds werefabricated into semimembranosus (SM) andadductor (AD) steaks, and goosenecks werefabricated into bottom round (biceps femoris)and eye of round steaks (semitendinosus).One 1-inch thick steak from each muscletype was not aged, and the other vacuumpackaged and aged at 32 ± 2°F. Color wasanalyzed after at least one-hour “bloom”using a Hunterlab MiniScan XESpectrophotometer with a minimum of twocolor measurements per steak. Color of topround (SM) steaks was analyzed on theexterior portion of the steak. Steaks werecooked in a Blodgett dual-air-flow convec-tion gas oven set at 325°F. Steaks weremonitored using a 30-gauge, type T thermo-couple and removed when they reached158°F. After cooked steaks were storedovernight at 37°F, a minimum of six 1/2-inchdiameter cores were taken parallel to thefiber orientation from each steak. Tender-ness was measured using an Instron Univer-sal Testing Machine with a Warner-BratzlerShear (WBS) attachment. Data were ana-lyzed as a randomized complete block design(blocking by steak) using Mixed Procedurein SAS (2000).


We found that aging steaks for 21 dayslowered (P<0.01) WBS values for loin strip,bottom, and eye of round steaks (Table 1).


60

WBS values for aged top round (SM) steakstended to be lower (P<0.06) than non-agedsteaks and aged top round (AD) steaks weresimilar (P=0.58) to non-aged steaks. Thedifference between aged and non-aged steakswas greatest for pre-selected tough strip loinsteaks. A partial explanation for this differ-ence in aging rate is that muscles from theround have a greater amount of connectivetissue, which may partially mask themyofibrillar improvement in tenderness dueto aging.

Aged loin strip and eye of round steakshad higher (lighter) instrumental L* colorvalues (P<0.01) than non-aged steaks. Fur-thermore, aged bottom round, top round(SM), and eye of round steaks had higher(redder) instrumental a* color values(P<0.01) when compared to non-aged steaks.Also, instrumental b* color values were

higher (more yellow; P<0.01) for bottomround, top round (SM), and eye of round andstrip loin (P=0.02) steaks than non-agedsteaks. No difference (P=0.37) in color wasfound for the top round (AD). Higher L*and a* values indicate a better "bloom."This improvement is partially due to anincrease in protein degradation and a de-crease in oxygen consuming enzymes. Thisallows oxygen to penetrate more deeplybelow the surface; thus the steak has abrighter cherry-red color.

Aging is effective for improving tender-ness and color of strip, bottom round, andeye of round steaks. It improved "bloom" ofloin strip, bottom round, eye of round, andtop round (SM) steaks. However, aging hadno effect on tenderness or color of the topround (AD) steaks.

Table 1. Effects of Aging on Warner-Bratzler Shear (WBS), L* (Lightness), a*(Redness), and b*(Yellowness) Values for Five Different USDA SelectMuscles

Item Non-Aged 21-day Aged SEM P-valueLoin Strip (longissimus; n = 30) WBS, lbs 13.65 10.03 0.55 <0.01 L* 42.8 46.5 0.44 <0.01 a* 23.7 24.2 0.26 0.17 b* 15.0 15.6 0.24 0.02Bottom Round (biceps femoris; n = 27) WBS, lbs 11.16 9.57 0.31 <0.01 L* 44.2 45.2 0.49 0.10 a* 23.9 27.0 0.34 <0.01 b* 15.1 18.7 0.32 <0.01Eye of Round (semitendinosus; n = 27) WBS, lbs 13.51 11.13 0.33 <0.01 L* 48.1 50.4 0.59 <0.01 a* 26.1 27.4 0.35 <0.01 b* 18.7 20.5 0.38 <0.01Top Round (semimembranosus; n = 18) WBS, lbs 8.25 7.71 0.26 0.06 L* 44.3 44.7 0.67 0.56 a* 25.8 27.5 0.40 <0.01 b* 16.9 19.1 0.40 <0.01Top Round (adductor; n = 18) WBS, lbs 8.71 8.97 0.33 0.58 L* 44.0 44.5 0.75 0.57 a* 25.4 25.9 0.40 0.37 b* 16.7 17.0 0.39 0.46


61


IMPROVING COLOR STABILITY OFBEEF TOP ROUND

L. M. Sammel, M. C. Hunt, and D. H. Kropf

Summary

The beef inside round muscle, especiallythe deep portion, has poor color stability, atroublesome condition for the meat industry.We examined influences of pre-rigor temper-ature and pH decline on chemistry of theinside (deep) semimembranosus (ISM) andoutside (surface) semimembranosus (OSM)in relation to initial color and stability.Cold-boned ISM had a slower chill rate;faster pH decline; more denatured protein;less metmyoglobin reducing ability, oxygenconsumption, and water holding capacity;and a lighter, less stable color than the OSM.Cold-boned steaks were two-toned in colorand discolored by day 3 of display. Hot-boned ISM and OSM chilled at the samerate, had similar pH declines, similar chemi-cal characteristics, and acceptable color traitsup to day 5 of display. Techniques that chillthe entire beef SM faster produced a moreuniform stable color, extended the color lifeof the ISM, and minimized rework anddiscounting.

(Key Words: Beef, Semimembranosus, ColorStability, Metmyoglobin, Reducing Activ-ity.)

Introduction

The beef semimembranosus (SM) is alarge, thick muscle of the inside round thatextends from the carcass surface to the femurbone. Following slaughter, the inner (deep)portion of the muscle chills slower than theouter (surface) portion, causing differencesin temperature/pH conditions. These influ-ence the oxidation and reduction of themuscle pigment and myoglobin, thus affect-ing color stability. In case-ready packagingsystems, the ISM discolors faster than the OSM.

Providing for more rapid chill of the deepportion (ISM) can slow pH decline and mayinfluence muscle biochemistry in a way thatprovides more color stability. Industry recog-nizes the color difference within the SMmuscle, but most color stability research onthe muscle does not identify from whatportion the samples were taken. We exam-ined the effects of temperature and pH de-clines of the ISM and OSM on initial color,color uniformity and stability, and musclepigment chemistry.


Ten carcasses (A-maturity; qualitygrades high Select to low Choice; yieldgrades 2 to 3) were chosen randomly at acommercial slaughter plant. Five carcasseswere electrically stimulated (continuous 48volts for 30 seconds); the other five carcasseswere not. One side of each carcass wasassigned randomly to be hot boned at 30-90min after stunning and the other half was leftintact for chilling. The hot-boning techniqueinvolved cutting the SM loose from theoutside round and tip muscles. The SM wasleft intact at the ventral surface of the hip-bone such that it hung away from the rest ofthe carcass, allowing chilled airflow to reachthe inner surface. All 10 carcasses werechilled at 0°C and spray chilled 5 min everyhour for 24 hours.

Temperature declines were monitored for24 hours in the ISM and OSM and pH mea-surements were taken at 1, 3, 5, 7, 9, 11, and24 hours postmortem. At 24 hours postmor-tem, inside rounds (NAMP #168) wereboned, trimmed, and vacuum packaged andstored until 9 days postmortem. The SM wascut into six steaks, each an inch thick. Each


62

steak was assigned randomly for analyses,which were conducted on both the inside(inner 1/3) and outside (outer 1/3) portions.One steak was displayed for 6 days, withinstrumental and visual color measurementstaken daily. The remaining five steaks wereused for analysis of shear force, metmyo-globin (Metmb) reducing ability, enzyme co-factors (NAD and NADH), myoglobin con-centration, heme iron, nonheme iron, proteindenaturation, lipid oxidation, oxygen con-sumption, water holding capacity, pH, andfiber type (succinic dehydrogenase activity).

Data were analyzed as a completelyrandomized split-split plot design where theSM muscle was the whole plot and storagewas the whole-plot treatment. Steaks werethe split-plots, and muscle location was thesplit-split plot. Proc Mixed procedure ofSAS was used to determine treatment differ-ences, and means were separated (P<0.05)using least significant differences.


With traditional cold-boning methods,the ISM chilled slower (P<0.05) than theOSM. However, hot boning allowed theISM to chill faster (P<0.05), resulting intemperature declines similar to cold-boned(CB) and hot-boned (HB) OSM (Fig. 1).Temperature decline affects postmortemglycolysis, and as a result, the pH decline ofCB ISM was faster (P<0.05) than for othertreatments (Fig. 2). The ultimate pH at 24hours postmortem was not affected by bon-ing method. Therefore, with cold-boning andhot-boning, we successfully produced post-mortem conditions within the ISM and OSMthat could result in chemical differencesaffecting color.

Color characteristics were similar be-tween CB OSM and both HB portions,whereas CB ISM was distinctly different.On day 0 of display, CB ISM was visually abrighter (P<0.05) cherry-red than the othertreatments; however, the more desirableappearance was lost quickly (Fig. 3). Novisual differences between treatments werefound on day 1 of display, but CB ISM wasthe most discolored on day 2 through 5.Both HB portions remained visually accept-

able throughout 5 days of display. CB ISMhad less (P<0.05) oxymyoglobin, greater(P<0.05) Metmb and lighter color (higher L*values) than CB OSM or both HB portionson day 2-5 of display. Panelists classifiedCB steaks as moderately two-toned and HBsteaks as uniformly colored during 5-daydisplay. Faster temperature and slower pHdeclines of the ISM with hot boning within30 to 90 min. following slaughter produceda more uniform, stable color.

Of the chemical characteristics measured,Metmb reducing ability, oxygen consump-tion, protein denaturation, and water holdingcapacity influenced the color stability of theISM and OSM. Cold-boned ISM had less(P<.05) Metmb reducing ability than CBOSM and both HB portions. Metmb reduc-ing ability of HB portions was higher(P<0.05) on day 0 of display than for CBportions, with no differences on day 2 or 4.Oxygen consumption was greater in CBOSM than CB ISM, with no differencesbetween HB portions. Proteins were moredenatured in CB ISM than in CB OSM andboth HB portions, which were not different.Low pH at high temperatures followingslaughter apparently denatured proteins inCB ISM, whereas the faster chill of HB ISMreduced protein denaturation. Denaturedproteins bind water poorly; therefore, CBISM had greater (P<0.05) expressible fluidsthan did CB OSM. Electrical stimulationhad a minimal affect on chemical character-istics of the ISM and OSM.

No differences in myoglobin, heme iron,and nonheme iron and only small differencesin pH, NAD, NADH, fiber type, and lipidoxidation were found between the ISM andOSM. Therefore, these characteristics werenot related to color or color stability.Warner-Bratzler shear force values were notaffected (P>0.05) by electrical stimulation orboning method, meaning we were able toimprove color stability of the ISM by hotboning, without altering tenderness.

Techniques that chill the entire beef SMfaster, with or without electrical stimulation,should be used to produce uniform, stablecolor by conserving reducing ability and


lessening protein denaturation. Extending ability to the meat industry by lowering retailthe color life of the SM can increase profit- rework and discounting.

454035

y 3o6255 20I- 15

1050

2 5 10 15 20 24Time postmortem, hours

Figure 1. Means for Temperature Declines Postmortem of Outer and Inner Portions of theInside Round Muscle (Semimembranosus = SM) That Were Intact or Hot BonedBefore Chilling. Means at the times postmortem with a different letter are different(P<0.05).

6.6

6.4

6.2

fo 6

5.8

5.6

5.41 3 5 7 9 11 24

Time postmortem, hours

Figure 2. Means for pH Declines Postmortem of Outer and Inner Portions of the InsideRound Muscle (Semimembranosus = SM) That Were Intact or Hot Boned BeforeChilling. Means at the times postmortem with a different letter are different ( P < 0 . 0 5 ) .

5

4.5

2 4H 3.55i 3

3 2.5?!' 2

1.5

1

0 1 2 3 4 5Display, days

Figure 3. Means for Visual Color Scores of Inside Round Steaks (Semimembranosus = SM)During Retail Display (Lower Visual Scores Are Redder and Less Discolored;Scores at 3.5 or Higher Are Unacceptable Color). Half of the steaks were fromcarcasses with the SM muscle intact or hotboned during chilling. Means on a displayday with a different letter are different (P<0.05).

63


1Department of Food Science and Nutrition, University of Minnesota, St. Paul, MN.

64


EFFECTS OF VASCULAR INFUSION WITH A SOLUTION OFSUGARS, SODIUM CHLORIDE, AND PHOSPHATES PLUS

VITAMINS C, E, OR C+E ON DISPLAY COLOR

E. J. Yancey, M. C. Hunt, M. E. Dikeman,P. B. Addis1, and E. Katsanidis1

Summary

Three groups of 12 (n=36) grain-fin-ished, crossbred Charolais steers were hu-manely slaughtered, and nine in each groupwere infused via the carotid artery with anaqueous solution of sugars, sodium chloride,and phosphates plus either vitamin C, E, or Cplus E. Three in each group served as non-infused controls. Vascular infusion improvedredness of longissimus thoracis (ribeye)muscles at 24 hours postmortem, but hadlittle effect on display color stability forsteaks. Vascular infusion with the solutionscontaining vitamin E improved color panelvisual evaluations of ground beef at 4 dayssimulated retail display.

(Key Words: Beef, Vascular Infusion,Color.)

Introduction

Vascular infusion near the end of bleed-ing is a relatively new process developed byMPSC, Inc. of Eden Prairie, MN. The pro-cess involves stunning animals by conven-tional captive bolt methods, and bleeding bysevering the jugular vein. Solutions of sub-strates are infused via the carotid artery,utilizing a pumping system at pressuresslightly below the blood pressures of restinglive cattle. Vascular infusion has improveddressing percentages as compared to non-infused control carcasses. The process wasdeveloped as a carcass rinsing technique thatalters the postmortem pH decline of beefmuscles and could improve beef color stabil-ity.

Vitamins C and E have antioxidant activ-ity. Vitamin C has improved color stabilityof ground beef when added during process-ing, and vitamin E improves steak andground beef display color stability when fedto cattle at supranutritonal levels. Our studywas designed to evaluate the effects of post-mortem infusion of vitamins C and E on beefdisplay color stability.


Three groups of 12 grain-finished, cross-bred Charolais steers were slaughtered usingconventional slaughter procedures on threeseparate slaughter dates. At each slaughterdate, nine were infused at 10% of live weightwith a solution of 98.52% water, .97% sug-ars, .23% sodium chloride, and .28% phos-phates (MPSC, Inc. Eden Prairie, MN) pluseither 500 ppm vitamin C (n=3; MPSC+C),500 ppm vitamin E (n=3; MPSC+E), or 500ppm vitamin C plus 500 ppm vitamin E(n=3; MPSC+C+E). The remaining three ateach slaughter date were bled conventionallyand served as non-infused controls. Car-casses were chilled at 35°F, with spray chillfor the first 12 hours, and ribbed between the12th and 13th ribs after 24 hours chill. Theexposed longissimus thoracis (LT) musclewas allowed to bloom for 20 minutes. In-strumental CIE L*, a*, and b* values werethen taken from the exposed LT.

Carcasses were fabricated at 48 hourspostmortem and sections of the LT, psoasmajor (PM), semimembranosus (SM), andquadriceps muscles were removed. Steaks 1inch thick were cut from LT, PM, and SM,


65

and then L*, a*, and b* color values wereobtained from the steaks after air exposurefor 20 min.

Subcutaneous fat was removed from therib and loin sections of each carcass andfrozen. The quadriceps muscle was groundand combined with the subcutaneous fat toproduce a 20% fat ground beef (GB). TheGB was mounded into 1 lb. portions, placedon foam trays, and overwrapped with oxygenpermeable polyvinylchloride film (23,250 cc/m2/24 h). GB displayed for 4 days at 35°Funder 150 foot candles of deluxe-warm-white fluorescent light with twice dailydefrost. GB was evaluated for CIE L*, a*,and b* color values and visual color by a

trained panel. The color panel utilized afive-point color scale (1 = very bright cherryred, 5 = dark red to tan or brown).


Color at 24 hours postmortemThe LT muscles from cattle infused with

MPSC+E were lighter colored (higher L*values) than those from both MPSC+C+Eand non-infused, control cattle at 24 hourspostmortem (P<0.05; Table 1). The LTmuscles from all infused cattle were morered (higher a* values) and more yellow(higher b* values) than those from non-infused, control cattle (P<0.05).

Table 1. Least Squares Means of CIE L*, a*, and b* Color Values for Longissimus ThoracisMuscles 24 h Postmortem and Longissimus Thoracis, Psoas Major, Outside and InsideSemimembranosus Steaks at 48 h Postmortem from Cattle Infuseda with EitherMPSC+Vitamin C (MPSC+C), MPSC+Vitamin C+Vitamin E (MPSC+C+E),MPSC+Vitamin E (MPSC+E), or Non-infused, Control Cattle (CON)

Muscle CON SE MPSC+C SE MPSC+C+E SE MPSC+E SELongissimus 24 h L* 39.0c 0.83 40.0bc 0.83 39.9c 0.83 42.4b 0.83thoracis 24 h a* 20.5c 0.53 22.2b 0.53 22.0b 0.53 23.2b 0.53

24 h b* 17.2c 0.65 19.7b 0.65 19.3b 0.65 21.1b 0.65

48 h L* 41.4c 0.79 41.4c 0.84 42.5bc 0.79 44.4b 0.7948 h a* 18.8 0.50 19.7 0.57 19.3 0.54 19.3 0.5448 h b* 16.6 0.65 17.3 0.69 17.0 0.65 18.0 0.65

Psoas 48 h L* 40.7c 0.72 39.6c 0.72 42.8b 0.72 43.4b 0.72major 48 h a* 20.4 0.47 21.0 0.47 20.7 0.47 20.2 0.47

48 h b* 17.9 0.61 18.1 0.61 18.5 0.61 18.4 0.61

Outside 48 h L* 38.9 0.78 38.4 0.74 39.6 0.74 40.8 0.70Semimembranosus 48 h a* 20.2 0.75 20.8 0.71 19.9 0.71 21.4 0.71

48 h b* 17.2 1.00 18.2 0.95 17.1 0.95 19.3 0.90

Inside 48 h L* 41.4 0.91 40.6 0.86 40.7 0.86 42.0 0.81Semimembranosus 48 h a* 22.7 0.56 23.0 0.53 23.2 0.53 23.5 0.50

48 h b* 21.3 0.71 20.7 0.67 21.4 0.67 22.1 0.64a98.52% water, 0.97% saccharides, 0.23% sodium chloride, and 0.28% phosphates infused at 10% oflive weight.b,cMeans within a row having different superscript letters differ (P<0.05).


66

Color at 48 Hours PostmortemAt 48 hours postmortem, LT steaks from

cattle infused with MPSC+E were lightercolored (higher L* values) than those fromboth MPSC+C-infused and non-infused,control cattle (P<.05; Table 1). The PMsteaks from both MPSC+E and MPSC+C+E-infused cattle were lighter colored (P<0.05)than from MPSC+C-infused and non-infused, control cattle. No differencesexisted among treatments for a* or b* values(P>0.05). No treatment differences existedfor SM L*, a*, or b* values.

Display Color EvaluationNo time × treatment interaction (P>0.05)

existed for GB L*, a*, or b* values.However, a time x treatment interactionexisted for the GB visual color panel scores(Table 2). On display days 1 through 4, theGB from MPSC+E-infused cattle was morecherry red (P<0.05) than that fromMPSC+C-infused cattle. The panel alsofound the GB from MPSC+E andMPSC+C+E-infused cattle to be more red(P<0.05) than that from non-infused, controlcattle on display day 4. Postmortemapplication of vitamin E via vascularinfusion can improve GB display colorstability.

Table 2. Time × Treatment Interaction Least Squares Means for Display Color Scores1 forGround Beef Obtained from Cattle Infuseda with Either MPSC+Vitamin C,MPSC+Vitamin C+Vitamin E, MPSC + Vitamin E, or Non-infused, Control Cattle

Display

Day CON SE MPSC+C SE MPSC+C+E SE MPSC+E SE

0 1.2 0.17 1.2 0.17 1.2 0.17 1.2 0.15

1 2.7bc 0.15 2.8b 0.13 2.5bc 0.15 2.4c 0.13

2 3.9b 0.17 3.9b 0.15 3.5bc 0.17 3.1c 0.15

3 4.5b 0.17 4.3bc 0.16 3.9cd 0.17 3.5d 0.15

4 5.0b 0.17 4.7bc 0.15 4.4cd 0.17 4.1d 0.15

a98.52% water, 0.97% saccharides, 0.23% sodium chloride, and 0.28% phosphates infused at 10% oflive weight.b,cMeans within a row having different superscript letters differ (P<0.05).1Display Color Score: 1 = Very bright cherry red or pale red, 2 = Bright cherry red or pale red, 3 =Slightly dark red to tan or brown, 4 = Moderately dark red to tan, 5 = Dark red to tan or brown.3.5 = Margin of acceptability.


1Appreciation is expressed to the NCBA Cattlemen’s Carcass Data Service, West Texas A&MUniversity for providing the data.2Division of Agriculture, West Texas A&M University, Canyon, TX.

67


RELATIONSHIPS AMONG BEEF CARCASSQUALITY AND CUTABILITY INDICATORS 1

T. E. Lawrence, D. A. King,T. H. Montgomery 2, and M. E. Dikeman

Summary

We evaluated beef carcass data (12th ribfat thickness, hot carcass weight, ribeye area,percentage of kidney-pelvic-heart fat, USDAyield grade, and USDA quality grade) from60,625 A-maturity steer and heifer carcasses.Data were analyzed to evaluate changes inquality grade with increasing fat thickness,changes in cutability indicators across qual-ity grades, and the association of hot carcassweight with ribeye area. Percentage ofUSDA Standard and Select carcasses de-creased, while Low Choice and PremiumChoice increased as fat thickness increased.Percentage of Low Choice remained steadyfor fat thickness of 0.56 - 0.60 in. and higher.Percentage of yield grade 4.0 or greatercarcasses increased dramatically as fat thick-ness increased beyond 0.60 in. Fat thick-ness, hot carcass weight, percentage ofkidney-pelvic-heart fat, and USDA yieldgrade increased, while ribeye area decreasedas quality grades improved. The associationbetween hot carcass weight and ribeye areadiffers from USDA requirements. Our re-cently collected data indicate that as hotcarcass weight increases, ribeye area in-creases at a slower rate than indicated byUSDA guidelines. Feeding cattle to a back-fat thickness of 0.51-0.55 in. will maximizequality grade while minimizing discounts foryield grade 4.0 or higher.

(Key Words: Carcass, Cutability Indicators,Quality Grade, Yield Grade.)

Introduction

USDA Quality and Yield grades areinversely related. To maximize carcassvalue, producers must adopt managementpractices that allow fed steers and heifers tobe marketed promptly when they havereached their quality grade potential, whileminimizing waste fat. The USDA yieldgrade formula was developed and adopted inthe 1960’s when the majority of cattle weresmall-framed, British-breed type. Changesin cattle type during the last 40 years indicatethat the USDA yield grade formula may needre-evaluation to reflect the current beef cattlepopulation. Our objectives were to evaluaterelationships among quality grade and yieldgrade traits; and to make recommendationsfor optimizing quality grade and yield grade.


Carcass data (n=60,625) were collectedfrom multiple plants throughout the nationduring 1995-1997 by the NCBA Cattlemen’sCarcass Data Service (CCDS). Carcasseswere sorted into five quality grades: Stan-dard, Select, Low Choice, Premium Choice,and Prime, and analysis of variance was usedto determine differences in cutability indica-tors by quality grade. Percentage of eachquality grade was calculated by 0.05 in. fatthickness increments to illustrate changes inquality grade with increased fat thickness.The data were also sorted by USDA hotcarcass weight groupings that correspond toribeye area requirements for calculating yield


68

grade. The USDA yield grade formula as-sumes a relationship between hot carcassweight (HCW) and ribeye area (REA) asfollows: REA = 0.012 * HCW + 3.8. Ad-justments to the yield grade of a carcass areapplied when the actual ribeye area is aboveor below this assumption. Ribeye areameans and standard deviations were calcu-lated at each USDA carcass weight incre-ment from 484 to 1034 lbs. to illustrate therelationship between USDA ribeye arearequirements and actual data from currentcattle types.


Cutability trait averages changed linearly(P<0.05) as USDA quality grade increased(Table 1). Fat thickness, hot carcass weight,percentage of kidney-pelvic-heart fat, andUSDA yield grade all increased as qualitygrade increased, but ribeye area decreased.Lower cutability carcasses, with smallerribeyes, had higher quality grades than moreheavily muscled, high cutability carcasses.

Percentage of Standard and Select de-creased steadily as fat thickness increased,while percentage of Premium Choice steadi-ly increased (Figure 1). Percentage of LowChoice increased up to a fat thickness of0.56-0.60 in., then leveled off. Percentage ofPrime slowly increased to a high of 3.4% ata fat thickness of 0.96-1.0 in. If cattle feed-ers target for an endpoint fat thickness of0.40 in., our data indicate that they could

expect 2.5% Standard, 51.1% Select, 38.9%Low Choice, 7.2% Premium Choice, and0.3% Prime while incurring only 0.1% yieldgrade 4.0 or higher. If cattle feeders targetfor at least 50% Choice cattle, our data indi-cate they should feed to a fat thickness of0.41-0.45 in. Feeding cattle to a fat thick-ness of 0.51-0.55 in. maximized qualitygrade while minimizing heavily discountedyield grade 4.0 or higher carcasses. Percent-age of yield grade 4.0 or higher carcassesincreased dramatically as fat thickness in-creased beyond 0.56-0.60 in.

Ribeye area increased at a slower rate(slope of 0.0082 vs. 0.012 in.2/lb) in relationto hot carcass weight than USDA standardssuggest (Figure 2). From 784 to 808 lbs.USDA standards and our data agree. How-ever, carcasses weighing less than 784 lbs.tend to have larger ribeyes than USDAguidelines require, which mathematicallylowers their yield grades below what ourdata suggest. Likewise, carcasses weighingmore than 808 lbs. tend to have smallerribeyes than required by USDA guidelines,which mathematically raises their yieldgrades above what our data suggest. USDAribeye area (in.2) requirements versus ourmean ribeye area (in.2) of selected hot car-cass weights are shown in Table 2. Thesedata suggest that the USDA yield gradingstandards should be revised to reflect ribeyearea × hot carcass weight relationships ofcurrent cattle types.

Table 1. Least Squares Means for Cutability Indicators of USDA Quality Grades

Variable Standard SelectLow

ChoicePremiumChoice Prime

n 1792 25,868 25,120 7377 468Fat thickness (in.) 0.27a 0.42b 0.50c 0.57d 0.60e

Hot carcass weight (lbs.) 719.0a 755.5b 763.5c 771.4d 772.3d

Ribeye area (in.2) 13.45e 13.21d 12.81c 12.67b 12.44a

Kidney-pelvic-heart fat % 1.92a 2.10b 2.13c 2.21d 2.30e

USDA yield grade 2.00a 2.60b 2.98c 3.25d 3.41e

a,b,c,d,eWithin a row, means lacking a common superscript letter differ (P<0.05).


Table 2. Comparison of the USDA Ribeye Area Requirement (in2) and Our Mean

Hot Carcass Weight400 500 600 700 800 900 1000 1100

USDA ribeye area 8.6 9.8 11.0 12.2 13.4 14.6 15.8 17.0Our mean ribeye area 10.1 10.9 11.7 12.5 13.4 14.2 15.0 15.8

100.0

90.0

80.0

5 70.0

.e‘ii 60.0dd 50.0sp 40.0

g 30.0.0’

20.0

-. ----.

._-. -_- -.- _...

.- -._. - .__._,

__-_._- ._.. .

.-.- --____ --- ..-.... ___ .._,

a t thickness (in.)

Quality Grade and Increasing 12th Rib Fat

16.0 ..- .

Is.0 CCDS REA - .0082(HCW + 6.8 - .. .-T1T.T-TTl

___.__.. - - _....-.__ -- OCCDS REAl- _ _ _

USDA HCW CROUPS

Figure 2. Comparison of USDA Ribeye Area x Hot Carcass Weight Requirements toActual Data.

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70


INTERRELATIONSHIPS AMONG CARCASSCHARACTERISTICS OF FEEDLOT STEERS AND

HEIFERS SELECTED FOR COMPETITION

D. A. King, T. E. Lawrence,M. E. Dikeman, and D. E. Schafer

Summary

We evaluated the interrelationshipsamong carcass characteristics of steers andheifers selected from commercial feedlotsfor competition in the Beef Empire Days liveand carcass contests. Because judgingcriteria are weighted heavily on cutability,the majority of cattle entered were trim andmuscular. Within this highly selected group,heifer carcasses had larger ribeye areas,lower hot carcass weights, more ribeyearea/100 lbs. of hot carcass weight, and ahigher percentage of kidney-pelvic-heart fatthan steers. However, steers graded USDAChoice or better 4% more often than heifers.Ribeye area, ribeye area/100 lbs. of hotcarcass weight, and percentage of kidney-pelvic-heart fat increased as dressing per-centage increased; however, 12th rib fatthickness had no effect on dressing percent-age. Percentage of carcasses grading USDAChoice or better tended to decrease withimproved dressing percentage. As 12th ribfat thickness increased, ribeye area andribeye area/100 lbs. of hot carcass weightdecreased whereas percentage of kidney-pelvic-heart fat and hot carcass weight ofsteers increased. As 12th rib fat thicknessincreased up to 0.50-0.59 inches, the percent-age of cattle that graded low Choice orhigher increased, but more finish did notresult in further increase in percentage of lowChoice or better. This study indicates thatribeye area is more closely related to eco-nomically important carcass characteristicsin trim, muscular cattle than previouslyidentified.

(Key Words: Beef, Carcass Characteristics,Ribeye Area, Fat Thickness, Quality Grade.)

Introduction

During the past four decades, the beefindustry has utilized large-framed, trim, fastgrowing cattle to increase efficiency andmeet consumer demands for lean, lower fatbeef. However, consumers still demand aflavorful, highly palatable product. Becauseof these demands, packers have developedpricing systems based on both quality andyield grades of carcasses. Most of thesepricing systems give a premium to cattle inthe upper two thirds of the Choice grade, andseverely discount carcasses below lowChoice or with yield grades of 4 or 5. Be-cause a significant percentage of cattle aresold on a carcass basis, hot carcass weightand dressing percentage are also important toproducers. Visual appraisal of live animalfinish is often the primary means of deter-mining when to market cattle. A commonbelief is that increasing fat thickness willincrease marbling as well as dressing per-centage. As a result, cattle are often overfedin an attempt to increase quality grades,often at the expense of cutability. Our objec-tive was to evaluate the relationships amongeconomically important carcass characteris-tics of steers and heifers that are very trimand muscular.


Live weight, hot carcass weight, ribeyearea (in.2), adjusted fat thickness (inches)percentage of kidney-pelvic-heart fat andUSDA quality grade were obtained fromsteers (n=532) and heifers (n=414) entered inthe 1994, 1995, 1999, and 2000 Beef EmpireDays live and carcass contests, because liveweights were available only from these years.Beef Empire Days is a live animal and car-


71

cass contest for feedlot cattle held annuallyin Garden City, KS. Fat thickness, ribeyearea, ribeye area/100 lbs. of hot carcassweight, hot carcass weight, percentage ofkidney-pelvic-heart fat, and percentage ofcarcasses grading USDA Choice or betterwere categorized according to gender (steeror heifer). Likewise, fat thickness, ribeyearea, ribeye area/100 lbs. of hot carcassweight, percentage of kidney-pelvic-heartfat, and percentage of carcasses gradingUSDA Choice or better were categorizedaccording to dressing percentage in incre-ments of 1% (range #60 to $69 %). Further-more, ribeye area, ribeye area/100 lbs. of hotcarcass weight, percentage of kidney-pelvic-heart fat, and percentage of carcasses gradingUSDA Choice or better were categorized by12th rib fat thickness (range #0.20 to $0.80inches) in 0.1 inches fat increments.


Because they had been selected for car-cass competition, cattle in this study weremuscular and trim (Table 1). Although fatthicknesses were equal, heifers had a higherpercentage of kidney-pelvic-heart fat and ahigher dressing percentage (64.8 vs. 64.3)than steers. This is consistent with conven-tional thinking that heifers generally arefatter than steers. However, heifers also hadlarger ribeye areas and ribeye areas per 100lb. of hot carcass weight than steers, whichcontradicts a traditional belief that heifers areless muscular than steers. Steers had heavierlive and hot carcass weights, and a higherpercentage of carcasses grading USDAChoice or better.

When categorized by dressing percent-age, ribeye area increased as dressing per-centage increased (Table 2). Adjusted 12th

rib fat thickness did not differ across dress-ing percentage categories. This indicatesthat fat thickness had little impact on dress-ing percentage. This might be because thecattle in this study were trim and did not re-

present a large range in fat thickness. Inhigh cutability cattle, muscling has a greaterimpact on dressing percentage than does fatthickness. The percentage of cattle gradingUSDA Choice or better tended to decline asdressing percentage increased.

When categorized by 12th rib fat thick-ness, percentage of kidney-pelvic-heart fatincreased as 12th rib fat thickness increased(Table 3), up to 0.40 to 0.49 inches. Ribeyearea and ribeye area per 100 pounds of hotcarcass weight decreased as 12th rib fat thick-ness increased, but little change occurred at0.60 to 0.69 inches or fatter. This indicatesthat lighter muscled cattle are fatter thanheavier muscled at the same carcass weight.As 12th rib fat thickness increased, hot car-cass weight increased slightly in steers;however, heifer hot carcass weights were notconsistently related to fat thickness, remain-ing relatively constant as fat thickness in-creased. Steers had heavier carcasses thanheifers for all fat thickness categories. In-creased fat thickness up to 0.50-0.59 inchesresulted in an increased percentage of cattlegrading USDA Choice or better (Figure 1).However, increasing 12th rib fat thicknessbeyond 0.59 inches resulted in no furtherincrease in the percentage of cattle gradingUSDA Choice or better. These results sug-gest that feeding high cutability cattle to a12th rib fat depth of 0.50-0.59 inches willallow cattle to express their genetic potentialfor marbling, but feeding cattle like these tohigher degrees of finish will not increase thepercentage of cattle grading Choice or better.

For these trim, muscular cattle, ribeyearea is more highly related to dressing per-centage and hot carcass weight than previ-ously believed. Twelfth rib fat thickness didnot impact dressing percentage. Further-more, increasing fat thickness up to 0.5inches increased the percentage of cattlegrading USDA Choice, but feeding cattlebeyond 0.5 inches did not improve qualitygrade.


72

Table 1. Least Squares Means of Carcass Characteristics of Cattle Selected forCompetition Categorized by Gender

Gender n

Fatthickness(inches)

Ribeyearea(in.2)

Ribeyearea/100 lbs.hot carcass

weight

Hotcarcassweight

Kidney-pelvic-heart fat

(%)

PercentageUSDA

Choice orbetter

Steer 532 0.43 14.42a 1.85a 782.3b 1.62a 48.68 Heifer 414 0.43 14.80b 2.06b 720.2a 1.76b 44.69

a,bWithin a column, means with a common superscript letter do not differ (P<0.05).

Table 2. Least Squares Means of Carcass Characteristics of Cattle Selected forCompetition Categorized by Dressing Percentage

Dressingpercentage n

Fatthickness(inches)

Ribeyearea(in.2)


weight

Kidney-pelvic-heart fat

(%)

PercentageUSDA

Choice orbetter

#60 16 0.31 12.85a 1.97abc 1.67bc 44.0061 41 0.38 13.90bc 1.99abc 1.67bc 48.0062 84 0.38 13.97bc 1.97ab 1.56a 54.7663 140 0.40 13.83bc 1.92a 1.67bc 44.9464 182 0.41 14.43c 1.94a 1.66b 50.2765 204 0.42 14.71c 1.96ab 1.72bc 40.5366 134 0.43 15.14d 1.96ab 1.74c 45.4567 80 0.42 15.58e 2.03c 1.68bc 37.2568 42 0.42 15.81e 2.02bc 1.87d 53.85

$69 23 0.49 15.90e 2.01abc 1.91d 35.29a,b,c,d,eWithin a column, means with a common superscript letter do not differ (P<0.05).

Table 3. Least Squares Means of Carcass Characteristics of Cattle Selected forCompetition Categorized by Fat Thickness (inches)

Fatthickness n

Ribeyearea (in.2)


weight

Kidney-pelvic-

heart fat (%)

Hot carcassweight(steers)

Hot carcassweight

(heifers)#.19 48 16.87e 2.26f 1.42a 765a 730b

.20-.29 152 15.37d 2.09e 1.60b 765a 712a

.30-.39 219 14.79c 2.00d 1.69c 773a 708a

.40-.49 218 14.43b 1.92c 1.75cd 778a 730b

.50-.59 155 14.08a 1.87b 1.74cd 794b 714ab

.60-.69 82 13.82a 1.82a 1.82d 801b 724ab

$.70 72 13.81a 1.80a 1.83d 811b 726ab

a,b,c,d,e,fWithin a column, means with a common superscript letter do not differ (P<0.05).


<.20 .21-.29 .30- .39 .40-.49 .50-.59 .60-.69 >.70

Fat thickness (in.)


74


RESPONSE OF HOLSTEIN STEERS FED A SOYBEAN HULL-BASED DIET TO AMINO ACID SUPPLEMENTATION

WHEN THE METHIONINE REQUIREMENT WAS MET

B. D. Lambert, E. C. Titgemeyer and C. A. Löest

Summary

A study was conducted to determine theresponse to amino acid supplementationwhen the first limiting amino acid(methionine) was provided in excess. Threeruminally cannulated Holstein steer calves(281 lb) were fed 4.8 lb of a soybean hull-based diet (87% soyhulls and 8% wheatstraw) daily. Methionine is the first limitingamino acid on diets of this type, and allsteers were abomasally infused with 10g/day of methionine to ensure that this re-quirement was met. Treatments consisted ofincreasing amounts (100, 250, or 400 g/day)of an amino acid mixture suppliedabomasally. Calves received decreasingamounts of supplemental energy in the formof volatile fatty acids and dextrose as aminoacid infusion increased in order for treat-ments to remain isoenergetic. Nitrogenbalance increased as amino acid supplyincreased, indicating that amino acids otherthan methionine limited protein deposition.The nitrogen balance change between the100 and 250 g/day amino acid treatmentswas greater than that from 250 to 400 g/d,suggesting that 250 g/day supplied amountsof amino acids near the requirement.

(Key Words: Amino Acids, Requirements,Steers.)

Introduction

Methionine is often the first limitingamino acid for growing cattle. We havepreviously evaluated the methionine require-ment of growing steers. However, littleresearch has been conducted to quantify therequirement of growing cattle for otheramino acids. The current study was con-

ducted to determine the optimal level ofinclusion of a supplemental amino acidmixture. Our results allow some initialconclusions about the magnitude of thedeficiencies of amino acids other thanmethionine, and will serve as a starting pointfor further work investigating amino acidneeds of growing cattle.


Three ruminally cannulated Holsteinsteer calves (281 lb initial weight) were usedin a 3 × 3 Latin square design. Steers weremaintained in individual metabolism cratesto allow for collection of feces and urine.We used nitrogen retention as an indicator oflean protein deposition. Treatments con-sisted of abomasal infusion of three gradedamounts (100, 250, or 400 g/day) of anamino acid mixture (Table 2). Steers werefed 4.84 lb/day (dry matter basis) of a soy-bean hull-based diet (Table 1) twice daily.All steers received 10 g/day L-methionine intheir infusate, which meets their requirementfor this first growth-limiting amino acid.Across treatments, the ratio of amino acidsremained constant (except for methionine).As supplemental energy, steers receivedacetate, propionate, and butyrateintraruminally. Steers also received supple-mental energy abomasally in the form ofglucose (Table 2). Glucose and volatile fattyacids decreased as the amount of amino acidsincreased to maintain constant energy supplyacross treatments.


Urinary nitrogen increased linearly(P=0.05) as infused amino acids increased.The magnitude of change in urinary nitrogen


75

was greater between the 250 and 400 g/daytreatments than between 100 and 250 g/d,which indicates that amino acid requirementshave been met, and excess amino acid nitro-gen was being wasted in the urine. Like-wise, nitrogen retention tended to increaselinearly (P=0.08) as amino acid infusionincreased. The observed changes in nitrogenretention correspond to increases in leantissue deposition of 0.92 lb/day between the100 and 250 g/day treatments and of 0.30lb/day between the 250 and 400 g/day treat-ments. The increase in nitrogen retentionbetween the 100 and 250 g/day treatmentsindicates that, at the 100 g/day amount, thesupply of at least one of the supplementala m i n o a c i d s w a s

limiting. The smaller increase between 250and 400 g/day treatments indicates that, eventhough 250 g/day did not fully meet thesteers needs, it was very close.

Our results suggest that the amino acidsupplement of 250 g/day was near to meetingthe steers amino acid needs when the firstlimiting amino acid (methionine) was sup-plied in excess. Although this research wasnot conducted under normal productionconditions, our results offer useful informa-tion toward the goal of balancing cattle dietson the basis of amino acids rather than crudeprotein.

Table 1. Diet Composition

Ingredient % of DM

Soybean hulls, pelleted 83.3

Wheat straw 7.6

Molasses, cane 3.7

Dicalcium phosphate 2.0

Sodium bicarbonate 1.0

Calcium carbonate 1.0

Urea 0.49

Magnesium oxide 0.40

Trace mineralized salta 0.29

Vitamin A, D, Eb 0.10

Sulfur 0.10

Bovatec-68c 0.02aComposition (%): NaCl (95 to 99), Mn (>0.24), Cu(>0.032), Zn (>0.032, I (>0.007), and Co (>0.004).bSupplied per lb of DM: 4090 IU vitamin A, 682 IUvitamin D and 18 IU vitamin E.cSupplied 15 mg lasalocid per lb of DM.


76

Table 2. Amino Acid, Volatile Fatty Acid, and Dextrose Infusates for Steer Calves

Amino acid supply (g/day)Infusate 100 250 400L-Glutamate 37 92.5 148Glycine 12.5 31.25 50L-Valine 5 12.5 20L-Leucine 7.5 18.75 30L-Isoleucine 5 12.5 20L-Lysine-HCl (feed grade; 78.8%)a 10 25 40L-Histidine-HCl-H2O (74.0%)b 2.5 6.25 10L-Arginine 5 12.5 20L-Threonine (feed grade; 98%)c 5 12.5 20L-Phenylalanine 8.75 21.875 35L-Tryptophan (feed grade; 98%)d 1.75 4.375 7L-Methionine 10 10 10Glucose 400 350 300Acetate 276 228 180Propionate 248 214 180Butyrate 53 46 40

aTo provide 31.5, 19.7 and 7.9 g/day L-Lysine.bTo provide 7.4, 4.6, and 1.9 g/day L-Histidine.cTo provide 19.6, 12.3 and 4.9 g/day L-Threonine.dTo provide 6.9, 4.3 and 1.7 g/day L-Tryptophan.

Table 3. Nitrogen Balance Data for Steer Calves Receiving Graded Levels of AminoAcid Mixtures

Amino acids (g/day) Contrast P valuea

Item 100 250 400 SEM Linear Quadraticn 3 3 3Nitrogen, g/dayInfused 13.7 33.0 52.2 - - -Dietary 45.0 45.0 45.0 - - -Total Intake 58.8 78.0 97.2 - - -Fecal 19.8 22.1 19.7 2.0 0.97 0.43Urinary 13.4 16.8 34.1 3.3 0.05 0.23Retained 25.6 39.0 43.4 3.9 0.08 0.44

aProbability of obtaining a difference of the observed magnitude by chance.


77


BRANCHED-CHAIN AMINO ACIDS FORGROWING CATTLE LIMIT-FED DIETS

BASED ON SOYBEAN HULLS

C. A. Löest, E. C. Titgemeyer,B. D. Lambert, and A. M. Trater

Summary

This study evaluated the effects ofbranched-chain amino acids on nitrogenretention and plasma branched-chain aminoacid concentrations. Five ruminally cannu-lated Holstein steers (387 lb) were used in a5 × 5 Latin square. Steers were limit-fedsoybean hull-based diets twice daily (7.5lb/day, as fed basis). Energy in the form ofacetate (400 grams/day) was continuouslyinfused into the rumen. Treatments werecontinuous abomasal infusions of 1) 115grams/day of a mixture of 10 amino acids, 2)10 amino acid mix with leucine removed, 3)10 amino acid mix with isoleucine removed,4) 10 amino acid mix with valine removed,and 5) 10 amino acid mix with all threebranched-chain amino acids removed. Nitro-gen retention decreased (P<0.06) in responseto removal of leucine, valine, or all threebranched-chain amino acids. Changes innitrogen balance of growing cattle limit-fedsoybean hull-based diets demonstrate limita-tions in the basal supply of leucine andvaline, but not isoleucine.

(Key Words: Leucine, Isoleucine, Valine,Steers.)

Introduction

For optimal lean muscle growth in cattle,the supply of postruminal amino acids (me-tabolizable protein) needs to meet animalrequirements. Therefore, the deficiency of asingle dietary essential amino acid may limitcattle growth. Although several reportssuggest that methionine is often first-limit-ing, other amino acids, such as lysine,arginine, histidine, or threonine, have also

been reported as limiting. However, there islittle research to support these findings.

Recent research at Kansas State Univer-sity demonstrated that an inadequate supplyof a branched-chain amino acid mixturecontaining leucine, isoleucine, and valinerestricted protein deposition of cattle limit-fed soybean hull-based diets. It was unclear,however, which of the branched-chain aminoacids were limiting. In the current study, weevaluated the effects of individual branched-chain amino acids on lean muscle growththat was estimated from nitrogen retentionand on plasma branched-chain amino acidconcentrations in cattle limit-fed soybeanhull-based diets.


Five ruminally cannulated steer calvesaveraging 387 lb initial body weight werehoused in individual metabolism crates andwere fed 7.5 lb/day as fed basis of a soybeanhull-based diet that consisted of 72% soy-bean hulls, 19% alfalfa, 5% molasses, and4% minerals/vitamins in equal portions twicedaily. To supply additional energy withoutincreasing ruminal microbial growth, steersreceived continuous infusions of acetate intothe rumen at a rate of 400 grams/day.

A 5 × 5 Latin square design was used,with 7-day periods; 3 days for adaptation totreatments and 4 days for collection of fecesand urine. Treatments were abomasal infu-sions of 115 grams/day of a mixture of 10amino acids, or the 10 amino acid mixturewith the branched chain amino acids,leucine, isoleucine, valine, or all three ofthese amino acids removed. The daily 10amino acid mixture infusion consisted of : L-


78

leucine (20 g), L-isoleucine (10 g), L-valine(10 g), L-lysine (15.8 g), L-methionine (10g), L-threonine (10 g), L-phenylalanine (10g), L-arginine (10 g), L-histidine (7.4 g), andL-tryptophan (4.9 g). Infusions into theabomasum were made by extending flexibletubing through the rumen cannula andreticulo-omasal orifice.

On days 4 through 7 of each period, totalfeces and urine were collected for determina-tion of nitrogen balance. Blood samples forplasma amino acid analysis were collectedfrom the jugular vein of each steer.


Because protein in soybean hulls ismostly degraded and utilized by rumenmicrobes, microbial protein is the primarysource of amino acids supplied to the smallintestine of cattle fed soybean hull-baseddiets. Limit feeding such a diet created asituation where both the energy and protein(amino acid) supplies were inadequate andlikely limited performance. To evaluatelimitations in the amino acid supply from thebasal diet, we ensured that energy would notbe the first nutrient to limit performance bysupplying energy in the form of acetate.Also, to evaluate which single amino acidsfrom the basal diet restricted performance,we ensured that performance was not limitedby any of the other essential amino acids byabomasally infusing the steers with mixturesof those essential amino acids. Infusing amixture that supplies slight excesses of all 10essential amino acids allowed the steers toperform at a rate that should not have beenrestricted by inadequate supplies of anyessential amino acids. Measuring changes innitrogen balance when a single amino acid isremoved from the 10 amino acid mixture

determined if the basal supply of that aminoacid by the soybean hull-based diet wasinadequate and therefore limiting. Nochange in nitrogen balance when an aminoacid is removed from the 10 amino acidmixture would demonstrate that the removedamino acid was not limiting.

Nitrogen retention decreased (P<0.05)when all three branched-chain amino acidswere removed from the 10 amino acid mix-ture (Table 1). Nitrogen retention also de-creased in response to the removal of leucine(P<0.06) or valine (P<0.05), but the removalof isoleucine had no effect. Thus the basalsupplies of leucine and valine were deficientand may limit animal performance.

Removal of all three branched-chainamino acids from the mixture of 10 aminoacids decreased (P<0.05) plasma concentra-tions of these branched-chain amino acids(Table 1). Removal of leucine alonedecreased its plasma concentrations(P<0.05), but increased plasma concentra-tions of both isoleucine and valine (P<0.05).However, removal of isoleucine or valinedecreased (P<0.05) only their own concen-trations in plasma, and did not significantlyalter plasma concentrations of the otherbranched-chain amino acids. These de-creases in plasma leucine, isoleucine, andvaline concentrations demonstrate that theirsupplies exceeded the requirements whensteers were infused with these amino acids inthe 10 amino acid mixture.

The nitrogen balance results demonstratethat the branched-chain amino acids, leucineand valine, but not isoleucine, are limitingwhen ruminal microbial protein is the pri-mary source of amino acids to the smallintestine of growing steers.


79

Table 1. Effects of Removing Leucine, Isoleucine, Valine, or All Three Branched-Chain Amino Acids from Postruminal Amino Acid Infusions on NitrogenBalance and Plasma Branched-Chain Amino Acid Concentrations ofGrowing Steers

Treatmentsa

Item 10AA -LEU -ILE -VAL -BCAA SEMSteers/treatment 5 4 5 5 5

Nitrogen ---------------- grams/day ---------------------- Intake 76.5 74.2 75.4 75.3 72.1 - Fecal 27.9 28.5 27.7 29.0 28.8 0.74 Urinary 22.9 22.8 22.9 23.8 22.1 0.81 Retained 25.7 23.1c 24.8 22.4b 21.2b 0.79

Plasma ------------------ µM ------------------------ Leucine 200 60b 190 217 60b 7.8 Isoleucine 148 296b 55b 154 88b 14.5 Valine 298 530b 289 123b 162b 20.8

a10AA = mixture of 10 essential amino acids; -LEU = leucine removed from 10AA; -ILE =isoleucine removed from 10AA; -VAL = valine removed from 10AA; -BCAA = leucine,isoleucine, and valine removed from 10AA.bDifferent from 10AA (P<0.05).cDifferent from 10AA (P<0.06).


1Department of Statistics.

80


EFFECTS OF WET CORN GLUTEN FEED AND INTAKELEVEL ON DIET DIGESTIBILITY AND RUMEN

PASSAGE RATE IN STEERS

S. P. Montgomery, J. S. Drouillard, E. C. Titgemeyer,J. J. Sindt, T. B. Farran, N. J. Pike,

C. M. Coetzer, A. M. Trater, and J. J. Higgins 1

Summary

Including 40% wet corn gluten feed(WCGF) in the diet increased total tractdigestion of organic matter and neutral deter-gent fiber (P<0.01), reduced total volatilefatty acid concentration (P<0.01), increasedrumen NH3 concentration (P<0.01),increased rumen pH, and tended (P<0.06) toincrease total tract digestion of starch. Fur-thermore, WCGF increased rumen passagerate of solid digesta (P<0.01) compared todiets containing no WCGF. Limit feedingreduced total tract digestion of organic mat-ter and neutral detergent fiber (P<0.01),decreased total volatile fatty acid concentra-tion (P<0.01), increased rumen NH3 concen-tration (P<.01), increased rumen pH at 0 and12 hours after feeding, reduced rumen pH at4 hours after feeding, and increased rumenliquid passage rate (P<0.02).

(Key Words: Wet Corn Gluten Feed, LimitFeeding, Digestibility, Passage Rate.)

Introduction

When cattle are allowed ad libitum ac-cess to feed, they typically eat several smallmeals over a 24-hour period, establishingrelatively steady-state rumen conditionsconducive to optimal fermentation. In con-trast, cattle that are limit-fed diets once dailygenerally consume their entire daily allot-ment of feed in large meals, at times con-suming their entire ration in only a fewhours. With high-energy diets, meal-eatingbehavior may negatively impact rumen fermenta-tion due to rapid intakes of highly fermentable

carbohydrates. Our study was conducted todetermine the effects of WCGF on dietdigestibility when included in diets fed adlibitum or limit-fed once daily.


Twelve ruminally cannulated steersweighing 1175 lb were used in an incompleteLatin square design experiment with a 2 × 2factorial arrangement of treatments to deter-mine the effects of WCGF and total intakelevel on diet digestibility and rumen passagerate. Treatments consisted of diets (Table 1)formulated to contain 20% alfalfa hay andsteam-flaked corn, with either 40% SweetBran® WCGF (dry basis) replacing steam-flaked corn or no WCGF. Cattle were fedonce daily, either ad libitum or limited to1.6% of body weight (dry basis). Two con-secutive 24-day periods were used; 18 daysfor adaptation, 4 days for collection, and a 2-day in situ period. Chromic oxide (digestionmarker, 10 g/head) was top dressed dailybeginning on day 11, and on day 19 steerswere ruminally dosed with 100 g of ytter-bium (Yb)-labeled alfalfa hay (solid phasemarker) and 200 mL of a cobaltethylenediamine tetraacetate (Co-EDTA)solution (liquid phase marker). Rumensamples were collected 24, 48, 72, and 96hours later and analyzed for concentrationsof Yb and Co. On days 19 to 22, rumenswere sampled once daily at 0, 4, 8, or 12hours after feeding, and fecal grab sampleswere obtained three times daily. On day 23,dacron bags containing 5 g of either steam-flaked corn, WCGF, or ground (2-mm)alfalfa hay were placed into the rumens of all


81

steers and removed after 3, 6, 12, or 48hours.

Table 1. Diet Composition (% of Dry Matter)

Treatments

Ingredients WCGF Corn Steam-flaked corn 39.9 65.9Alfalfa hay 19.9 19.4Wet corn gluten feed 38.3 -Soybean meal - 7.4Cane molasses - 4.8Urea 0.1 1.0Limestone 1.2 0.8Calcium phosphate - 0.3Sodium chloride 0.4 0.3Potassium chloride 0.1 -Vitamin/trace mineral premixa 0.1 0.1

Crude protein, analyzed 16.8 16.3aFormulated to provide (total diet dry matter): 1,200IU/lb vitamin A, 0.1 ppm cobalt, 10 ppm copper, 0.6ppm iodine, 60 ppm manganese, 0.2 ppm selenium, 60ppm zinc, and 30 g/ton of Rumensin®.


Digestibility and passage rate data areshown in Table 2. WCGF increased drymatter intake of ad libitum fed steers(P<0.01), increased total tract digestibility of

organic matter and neutral detergent fiber(P<0.01), and reduced ruminal total volatilefatty acid concentration (P<0.01)(Table 3).This reduced volatile fatty acid concentrationmay have contributed to the higher rumenpH at 8 and 12 hours after feeding (Figure 1)for WCGF. WCGF also increased rumenNH3 concentration (P<0.01), suggesting itsprotein is rapidly degraded. Steers fedWCGF had higher rumen solid digesta pas-sage rates (P<0.01) than those withoutWCGF. Limit feeding decreased total tractdigestion of both organic matter and neutraldetergent fiber (P<0.01), reduced total vola-tile fatty acid concentration (P<0.01), andincreased rumen NH3 concentration(P<0.01). The lower rumen pH at 4 hoursafter feeding, along with an increase inrumen liquid passage rate (P<0.02), may beresponsible for the reduction in digestibility.Total tract starch digestion was not affectedby intake level. During the in situ trial (datanot shown) no differences in rate of drymatter disappearance for alfalfa hay, steam-flaked corn, or WCGF were observed. Weconclude that inclusion of WCGF at 40% ofdietary dry matter may increase organicmatter and neutral detergent fiber digestion.Limit feeding of high-energy diets once dailymay depress organic matter and neutraldetergent fiber digestibility due to a lack ofsteady-state rumen conditions.

Table 2. Effect of Wet Corn Gluten Feed and Intake Level on Total Tract Apparent Digestibility,Rumen Passage Rate, and Rumen Volume

TreatmentWCGF Corn P-valuea

Item Ad Lib Limit-Fed Ad Lib Limit-Fed SEM Diet Intake D × IIntake, lbs Dry matter 30.2 19.5 24.6 19.5 0.97 0.03 <0.01 0.03 Organic matter 28.1 18.2 23.3 18.4 0.90 0.04 <0.01 0.03 Neutral detergent fiber 9.2 6.0 5.0 4.0 0.29 <0.01 <0.01 <0.01 Starch 9.6 6.1 11.6 9.0 0.43 <0.01 <0.01 0.40Digestibility, % Organic matter 86.9 80.2 84.0 79.5 0.50 <0.01 <0.01 0.08 Neutral detergent fiber 76.1 62.7 58.4 47.9 2.1 <0.01 <0.01 0.51 Starch 97.2 96.9 93.1 94.5 1.4 0.06 0.70 0.59Particulate kinetics Passage rate, %/hour 3.7 3.4 2.7 2.9 0.15 <0.01 0.58 0.11 Turnover time, hour 27.3 30.9 38.1 36.4 1.7 <0.01 0.62 0.18Fluid kinetics Passage rate, %/hour 2.2 3.0 2.3 2.9 0.22 0.97 0.02 0.50 Turnover time, hour 47.3 33.3 46.1 38.2 3.8 0.65 0.03 0.46Rumen volume, liters 209.2 100.1 146.4 99.5 16.9 0.11 <0.01 0.12aProbability that differences of the magnitude observed were due to random chance.


Table 3. Effect of Wet Corn Gluten Feed and Intake Level on Total VFA Concentrations,Acetate:Propionate Ratios, Molar Percentages of VFA, and Rumen AmmoniaConcentrations

Treatment

WCGF Corn P-value”Ad Lib Limit-Fed Ad Lib Limit-Fed SEM Diet Intake D x I

Total VFA, m M 111.7 96.8 127.8 111.3

Acetate, % 50.0 53.9 49.2 52.3

Propionate, % 28.0 24.5 36.1 29.5

Butyrate, % 15.9 13.4 11.1 11.8

Isobutyrate, % 1.2 2.1 0.7 1.1

Valerate, % 3.5 3.5 1.4 2.2

Isovalerate,% 1.4 2.6 1.5 3.1

Acetate:propionate 1.9 2.3 1.4 1.9

4.1 co.01 co.01 0.77

1.1 0.30 0.01 0.72

1.9 0.01 0.01 0.410.82 co.01 0.16 0.03

0.21 0.01 0.01 0.310.42 co.01 0.29 0.27

0.49 0.45 0.02 0.65

0.16 0.01 0.02 0.53

NH3, mM 6.8 10.0 3.1 5.4 0.92 co.01 0.01 0.61

aProbabilityProbability that differences of the magnitude observed were due to random chance.

7.0

6.8

6.6

6.4

6.2

E 6.05.8

5.6

5.4

5.2

+ WCGF Ad Lib

-El - WCGF Limit-Fed

*Corn Ad Lib

__ SEM = 0.078

0 4 8 12

Hour

Figure 1. Effect of Wet Corn Gluten Feed and Intake Level on Rumen pH.

82


1Cargill Corn Milling, Blair, NE.

83


PERFORMANCE OF BEEF HEIFERS LIMIT-FED GROWING DIETS CONTAINING ALFALFA HAY

AND WET CORN GLUTEN FEED

S. P. Montgomery, J. S. Drouillard, J. J. Sindt, T. B. Farran, N. J. Pike, C. M. Coetzer, H. J. LaBrune,

A. M. Trater, R. D. Hunter, and R. A. Stock 1

Summary

Three hundred thirty-nine crossbred beefheifers were used in a 99-day growing studyto identify optimum combinations of alfalfahay and wet corn gluten feed (WCGF) inlimit-fed growing diets. Diets contained 10,20, or 30% ground alfalfa hay, and 0, 40, or68% Sweet Bran® WCGF (dry basis) in a 3 ×3 factorial arrangement of treatments. Aninteraction occurred (P<0.05) between levelof alfalfa hay and level of WCGF for bothaverage daily gain and feed efficiency.Increasing the levels of alfalfa hay or WCGFreduced cattle performance, with the excep-tion of the 30% alfalfa hay and 40% WCGFdiet, which supported average daily gainssimilar (P>0.10) to diets containing 20 or30% alfalfa hay and no WCGF. Feed effi-ciencies for the 30% alfalfa hay and 40%WCGF diet were better (P<0.05) than thediet containing 30% alfalfa hay and noWCGF. Dry matter intake as measured twohours after feeding increased linearly(P<0.01) with increasing levels of alfalfahay, and decreased linearly (P<0.01) withincreasing levels of WCGF. This studysuggests that including WCGF at 40% of thediet (dry basis) can effectively replacesteam-flaked corn in limit-fed diets contain-ing 20 or 30% alfalfa hay.

(Key Words: Wet Corn Gluten Feed, AlfalfaHay, Limit Feeding, Growing.)

Introduction

Wet corn gluten feed, a by-product ofcorn wet milling, consists mainly of corn

bran and corn steep liquor. Because of highlevels of corn bran, WCGF can supply addi-tional energy for maintenance and growthwithout the reduction in fiber digestion oftenseen when substantial quantities of high-starch ingredients (grain) are fed to cattleconsuming high-roughage diets. This studywas conducted to identify optimum combina-tions of alfalfa hay and WCGF in limit-fedgrowing diets containing steam-flaked corn.


Three hundred thirty-nine crossbred beefheifers averaging 609 lb were used in arandomized complete block experiment. Tominimize differences in gastrointestinal tractfill, heifers had ad libitum access to a com-mon diet for 15 days preceding the growingstudy. Heifers were then blocked by weightand allotted to pens containing four to sevenhead per pen, with six pens per treatment.Treatments (Table 1) consisted of dietscontaining 10, 20, or 30% ground alfalfahay, and 0, 40, or 68% Sweet Bran WCGF(dry basis) in a 3 × 3 factorial arrangement.All diets provided 30 grams of Rumensin®

per ton of dry matter and were fed once dailyat 1.6% of body weight (dry basis) for 84days. On days 8, 22, 37, 51, 64, and 79,unconsumed feed was removed from thefeed bunks 2 hours after feeding, immedi-ately weighed, and returned to the bunk inorder to measure rate of feed consumption.Prior to obtaining final weights, heifers hadad libitum access to a common diet for 15days.


84


Performance data are shown in Figures 1and 2. There was an interaction betweenalfalfa hay and WCGF level in the diet.Increasing the level of alfalfa hay andWCGF reduced growing performance ofheifers, with the exception of the diet con-taining 30% alfalfa hay and 40% WCGF.Heifers fed that diet had average daily gainssimilar (P>0.10) to those consuming dietscontaining 20 or 30% alfalfa hay and noWCGF. They also had improved feed effi-ciencies compared to heifers fed the dietcontaining 30% alfalfa hay and no WCGF( P < 0 . 0 5 ) . D r y m a t t e r

intake was not different among treatments(P>0.05) (11.4 ± .4 lb/day), so these resultsindicate a positive associative effect ofWCGF on the digestibility of alfalfa hay inthe diet containing 30% alfalfa hay and 40%WCGF. Increasing the level of alfalfa hay inthe diet increased (P<0.01) dry matter intakeas measured 2 hours after feeding (Figure 3),whereas increasing the level of WCGF de-creased (P<0.01) dry matter intake. Weconclude that the value of WCGF relative tosteam-flaked corn increases in diets contain-ing greater amounts of roughage whenWCGF is included at 40% of the diet drymatter.

Table 1. Experimental Diets (% of Dry Matter)

Treatments

% Alfalfa Hay 10 10 10 20 20 20 30 30 30

Ingredients % WCGF 0 40 68 0 40 68 0 40 68

Steam-flaked corn 73.4 48.6 20.0 65.3 39.2 10.0 57.1 29.5 -

Alfalfa hay 9.8 9.9 10.0 19.6 19.9 20.1 29.5 30.0 30.3

Wet corn gluten feed - 38.9 67.1 - 39.0 67.3 - 39.1 67.6

Soybean meal 9.0 - - 7.6 - - 6.2 - -

Cane molasses 4.9 - - 4.9 - - 4.9 - -

Urea 1.0 0.3 - 1.0 0.1 - 1.0 - -

Limestone 1.2 1.6 2.3 0.8 1.2 2.0 0.5 0.9 1.6

Calcium phosphate 0.2 - - 0.3 - - 0.3 - -

Sodium chloride 0.4 0.4 0.4 0.4 0.4 0.4 0.4 0.4 0.4

Potassium chloride - 0.2 0.1 - 0.1 0.1 - - -

Vitamin/trace mineral premixa 0.1 0.1 0.1 0.1 0.1 0.1 0.1 0.1 0.1

Crude protein, analyzed 16.1 16.5 20.1 16.1 16.8 20.8 16.1 17.0 21.4

aFormulated to provide (total diet dry matter): 1,200 IU/lb vitamin A, 0.1 ppm cobalt, 10 ppm copper,0.6 ppm iodine, 60 ppm manganese, 0.2 ppm selenium, 60 ppm zinc and 30 g/ton of Rumensin.


2.3 -El - 4 0 % W C G F

d 2.1- 6 8 % W C G F

#ax4 1.9

1.7

‘1.5

1 0 2 0 3 0

Alfalfa Hay Level, %

Figure 1. Average Daily Gain of Heifers Limit-Fed Growing Diets Containing 10, 20, or30% Alfalfa Hay and 0, 40, or 68% Wet Corn Gluten Feed. Interactionbetween alfalfa hay and WCGF level in diet (P<0.05).

7.0

I SEM = 0.14 T I6.5

-II -40% WCGF

-68% WCGFI I

10 2 0 3 0

Alfalfa Hay Level, %

Figure 2. Feed:Gain of Heifers Limit-Fed Growing Diets Containing l0, 20, or 30%Alfalfa Hay and 0, 40, or 68% Wet Corn Gluten Feed. Interaction betweenalfalfa hay and WCGF level in diet (P<0.05).

11.0 , I

10.0

9.0

8.0

7.0

6.0

10 2 0 3 0 0 40 68

Alfalfa Hay Level, % WCGF Level, %

Figure 3. Dry Matter Intake as Measured Two Hours After Feeding. Linear effect ofalfalfa hay (P<0.01) and linear effect of WCGF (P<0.0l).

85


86


SOYBEAN HULLS AND ALFALFA FORLIMIT-FED CATTLE

A. M. Trater, E. C. Titgemeyer,C. A. Löest, and B. D. Lambert

Summary

We evaluated the optimal level of alfalfainclusion in limit-fed, soybean hull-baseddiets. Steers were fed soybean hull-baseddiets containing 0 to 30% alfalfa or alfalfaalone. Feed intakes were lower for alfalfathan for soybean hull-based diets.Digestibilities of dry matter and neutraldetergent fiber were lower (P<0.05) foralfalfa than for diets containing soybeanhulls. Dry matter and neutral detergent fiberdigestibilities were similar for differentlevels of alfalfa in diets containing soybeanhulls, although there were positive associa-tive effects between soybean hulls and al-falfa. Rates of liquid passage from the ru-men were higher for alfalfa than for soybeanhull-containing diets, and increased as alfalfawas added to the soybean hull diets. Solidpassage rates also increased with increasingamounts of alfalfa in soybean hull-containingdiets. Adding 30% alfalfa to primarily soy-bean hull diets led to positive associativeeffects on diet digestibility, but alfalfa addi-tions increased liquid and solid passage rates,suggesting that the benefit was not a result ofslower passage of soybean hulls from therumen.

(Key Words: Soybean Hulls, Alfalfa, Steers,Digestion, Passage Rate.)

Introduction

Soybean hulls present an opportunity tothe beef and dairy cattle industries becausethey contain a large amount of potentiallydigestible fiber. Consequently, they may beincluded in high-forage diets to increaseenergy content without decreasing fiberdigestibility. However, they have a short

retention time in the rumen due to their smallparticle size and high specific gravity, whichmay limit their digestibility and subsequentanimal performance. Previous research atKansas State University indicated that re-stricting the intake of soybean hull-baseddiets to 1.5 or 2.25% of body weight (BW) inan attempt to slow passage did not changedigestibility, and, therefore, probably did notchange the passage rate of soyhulls from therumen. An alternative method to decreasethe rate of passage of feed from the rumenmay be to include forage in the diet.

Our experiments were designed to inves-tigate changes in digestibility and passagerate of soybean hull-based diets as gradedlevels of alfalfa were added.


Twenty Holstein steers (702 lb initialBW) were used in a randomized completeblock design. They were housed in partiallycovered, individual pens, and had free accessto water. Diets were fed once daily at 1.75%of body weight (dry matter basis) . Treat-ments were a soybean hull mix (95.7%soybean hulls, 3% molasses, 0.5% urea,0.8% mineral mix) fed with 0, 10.4, 20.7,and 30.9% coarsely chopped alfalfa hay(100:0, 90:10, 80:20, 70:30, respectively), oralfalfa alone (0:100). The experiment lasted16 days, with total fecal collection (in bags)during the last 6 days. Fecal bags wereemptied daily. Liquid and solid passagerates from the rumen were determined usingfecal samples taken once daily, immediatelyprior to fecal bag emptying. These sampleswere analyzed for concentrations of liquid(chromium EDTA) and solid (ytterbiumchloride) ingesta markers.


87


Intakes, digestibilities, and passage rates(liquid and solid) are presented in Table 1.Despite restriction of feed to 1.75% of BW,some steers refused part of their daily ration.This produced dry matter intakes that werelower (P<0.05) for alfalfa alone than fordiets containing soybean hulls. The alfalfawe used contained appreciable dust, whichmay have contributed to the lower intakes forthe 0:100 diet. Intakes for the 100:0, 90:10,80:20, and 70:30 diets were similar.

Dry matter digestibility was lower foralfalfa alone (P<0.05) than for diets contain-ing soybean hulls. Similar results have beenfound with other forage sources. There wasno significant difference in dry matter digest-ibility among diets containing soybean hulls,although there were positive associativeeffects on dry matter and neutral detergentfiber digestibilities for combinations ofsoybean hulls and alfalfa. Our originalhypothesis was that forage additions wouldslow passage from the rumen and therebyallow more time for digestion. However,solid passage rate actually increased withalfalfa additions to soybean hull-containingdiets. Liquid passage rates were higher

(P<0.05) for alfalfa alone than for dietscontaining soybean hulls. Further, liquidpassage rate increased linearly (P<0.05) asalfalfa was added to the soybean hull mix.Because soybean hull particles are small andhave a high specific gravity, they have thepropensity to pass rapidly from the rumen.The increase in liquid passage rate withalfalfa addition may have hastened the pas-sage of soybean hulls by carrying the smallsolid particles out of the rumen as part of theliquid phase. Although pH was not mea-sured in this experiment, other researchindicates that diets consisting primarily ofsoybean hulls can result in low ruminal pH.At a low rumen pH, fiber digestion can beinhibited. Thus, the positive associativeeffects for digestion with the addition ofalfalfa might have resulted from an increasein rumination and salivary flow and, there-fore, a higher rumen pH. Ruminal pH alsomay have been affected by alfalfa additionbecause alfalfa itself has a high bufferingcapacity. If rumen pH was sub-optimal forsteers fed only soybean hulls, an increase inpH with alfalfa addition to the soybean hull-containing diets may have increased the rateof fiber digestion, and this may explain theobserved associative effects.

Table 1. Intakes, Digestibilities, Passage Rates, and Associative Effectsa for Digestibilitiesand Passage Rates for Mixtures of Soybean Hulls and Alfalfa

Soybean Hull Mix:Alfalfa

Item 100:0 90:10 80:20 70:30 0:100 SEM

Dry matter Intakeb, lb/day Digestibilityb, %

11.967.5

11.270.9 (6)

12.167.2 (3)

12.570.9 (10e)

9.956.2

0.702.00

Neutral detergent fiber Intakeb, lb/day Digestibilityb, %

7.066.1

6.870.5 (9)

7.365.4 (4)

7.368.6 (11e)

5.547.4

0.372.30

Liquid passageb,c, %/hour 4.6 6.2 (22) 5.6 (7) 7.4 (24e) 7.7 0.53

Solid passagec,d, %/hour 4.1 5.0 (18) 4.2 (4) 7.0 (42e) 4.0 0.47aAssociative effects (%, in parentheses) calculated as (observed - expected)/expected, whereexpected was calculated as a weighted average based on the proportions of soybean hulls andalfalfa in the diet. bAlfalfa vs soybean hull-containing diets (P<0.05). cLinear effect of alfalfawithin soybean hull-containing diets (P<0.05). dCubic effect of alfalfa within soybean hull-containing diets (P<0.05). eAssociative effect different from 0 (P<0.05).


1Elanco Animal Health, Indianapolis, IN.

88


RUMENSIN®-TYLAN® COMBINATIONS IN LIMIT-FED GROWING DIETS: EFFECTS ON GROWING AND FINISHING

PERFORMANCE AND CARCASS CHARACTERISTICS

S. P. Montgomery, J. S. Drouillard, T. B. Farran, J. J. Sindt, C. M. Coetzer, J. N. Pike, A. M. Trater, H. J. LaBrune, R. D. Hunter, and S. B. Laudert 1

Summary

Five hundred seventy-two crossbred beefheifers were used to compare gain and feedefficiency of cattle consuming restrictedquantities of energy-dense growing dietscontaining varying concentrations ofRumensin® and Tylan®. Growing treatmentsconsisted of providing Rumensin at 30 gramsper ton of dry matter (R30), or 250 mg perhead per day (R250). A third treatmentconsisted of a Rumensin/Tylan combination,providing 250 and 90 mg per head per day ofRumensin and Tylan, respectively(R250/T90). Average daily gain and feedefficiency during the growing phase were notdifferent (P>0.90) among treatments. Heif-ers that received R250/T90 during the grow-ing phase exhibited lower dry matter intakes(P<0.05) during the finishing phase. Al-though not significant (P>0.50), R250/T90increased finishing-phase feed efficiency by6.1 and 3.5% compared to R30 and R250,respectively. Liver abscesses were lower(P<0.10) for R250/T90 and R30 than R250.

(Key Words: Rumensin, Tylan, Limit Feed-ing.)

Introduction

Food and Drug Administration regula-tions currently limit Rumensin concentra-tions to not more than 30 grams per ton ofdiet (90% dry basis). Although this level isadequate to enhance growth and increasefeed efficiency in cattle fed ad libitum, itmay be less than optimum when cattle arefed restricted amounts of high-concentrate grow-

ing diets. Furthermore, cattle grown onhigh-concentrate diets and then subsequentlyfed finishing diets are subjected to prolongedperiods of high grain intake. Feeding high-grain diets for extended periods may predis-pose cattle to ruminitis, thus increasing theincidence of liver abscesses. This study wasconducted to determine if higher levels ofRumensin as well as the use of Tylan inlimit-fed, high-energy growing diets wouldimprove cattle performance during the grow-ing phase and subsequent finishing period.


Five hundred seventy-two crossbred beefheifers weighing 593 lb were used in a ran-domized complete block design. Heiferswere fed a common diet ad libitum for 14days preceding the growing study to mini-mize differences in gastrointestinal tract fill.Heifers were blocked by weight and allottedto pens containing 47 to 48 animals per pen,with four pens per treatment. Growing diets(Table 1) provided 30 grams of Rumensinper ton (dry matter basis), 250 mg ofRumensin per head per day, or 250 mg ofRumensin plus 90 mg of Tylan per head perday. Diets were fed once daily at 1.6% ofbody weight (dry matter basis) for 99 days.Intakes were adjusted weekly, assuming anaverage gain of 2 lb per head daily. Prior toobtaining final weights for the growingphase, cattle were provided ad libitum accessto a common diet for 14 days. Heifers werethen stepped up to a common finishing diet,fed for 80 days, and slaughtered. The finalfinishing diet provided 300 mg of Rumensin


89

and 90 mg of Tylan per day and was fedonce daily ad libitum.


Increasing Rumensin intake of heifersconsuming limit-fed growing diets did noteffect weight gain or feed efficiency(P>0.90) during the growing phase (Table 2),which suggests that 30 grams of Rumensinper ton was sufficient to elicit maximalgrowth response. Heifers receiving the R30treatment averaged 168 mg of Rumensin perhead per day. Finishing average daily gainswere not significantly different (P>0.80)among treatments (Table 3). Finishing dry

matter intakes were lower (P<0.05) forheifers that had received R250/T90 duringthe growing phase, resulting in a numericalimprovement in feed efficiency compared toR30 and R250 (6.1% and 3.5% respectively).Liver abscesses were lower (P<0.10) forR250/T90 and R30 compared to R250, andthe percentage of yield grade 2 carcasses wasgreater (P<0.05) for R250/T90 compared toR30. The results of this study suggest thatfeeding 250 mg of Rumensin as well as 90mg of Tylan per day to heifers consuminglimit-fed, high-energy growing diets mayreduce dry matter intake during the subse-quent finishing period without negativelyaffecting gain.

Table 1. Experimental Diets (% of Dry Matter)

Growing1

Ingredient R30 R2502 R250/T903 Finishing4,5

Steam-flaked corn 66.4 67.8 67.8 80.7Alfalfa hay 14.7 15.0 15.0 6.8Soybean meal 8.5 8.7 8.7 3.0Cane molasses 3.9 4.0 4.0 4.4Tallow 2.1 2.1 2.1 2.1Urea 1.1 1.1 1.1 1.3Limestone 1.0 1.0 1.0 1.2Sodium chloride 0.4 0.4 0.4 0.3Potassium chloride - - - 0.1Ammonium sulfate - - - 0.2Calcium phosphate 0.3 0.3 0.3 0.1Vitamin/trace mineral premix 0.1 0.1 0.1 0.1Rumensin premix 2.1 - - -Rumensin 30 g/ton 250 mg/day 250 mg/day 300 mg/dayTylan - - 90 mg/day 90 mg/dayMelengestrol Acetate - - - .5 mg/day

Crude protein, analyzed 15.8 16.0 16.0 14.51Vitamin/trace mineral premix formulated to provide (total diet dry matter): 1,200 IU/lbvitamin A, 0.1 ppm cobalt, 10 ppm copper, 0.6 ppm iodine, 60 ppm manganese, 0.3 ppmselenium, and 60 ppm zinc.2,3 Rumensin/Tylan supplement fed at 0.22 lb per head per day (dry matter basis).4Vitamin/trace mineral premix formulated to provide (total diet dry matter): 1,200 IU/lbvitamin A, 0.1 ppm cobalt, 8 ppm copper, 0.5 ppm iodine, 50 ppm manganese, 0.3 ppmselenium, and 50 ppm zinc.5Rumensin/Tylan/Melengestrol Acetate supplement fed at 0.44 lb per head day (dry matterbasis).


90

Table 2. Performance During the Growing Phase for Heifers Limit-Fed GrowingDiets Providing 30 Grams/Ton of Rumensin (R30), 250 mg of Rumensin perHeifer Daily (R250), or 250 mg of Rumensin plus 90 mg of Tylan per HeiferDaily (R250/T90)

Growing DietItem R30 R250 R250/T90 SEMNo. of heifers 190 192 190Initial weight, lb 595 587 596 13.1Final weight, lb 811 801 811 13.0Dry matter intake, lb/day 11.2 11.3 11.4 0.20Average daily gain, lb 2.18 2.16 2.17 0.04Feed:gain 5.15 5.21 5.24 0.15

Table 3. Finishing Performance and Carcass Characteristics Following a GrowingPeriod During Which Heifers Were Fed Diets Providing 30 Grams/Ton ofRumensin (R30), 250 mg of Rumensin per Heifer Daily (R250), or 250 mgof Rumensin plus 90 mg of Tylan per Heifer Daily (R250/T90)

Previous Growing DietItem R30 R250 R250/T90 SEMNo. of heifers 190 192 190Initial weight, lb 811 801 811 13.0Final weight, lb1 1054 1044 1049 14.7Dry matter intake, lb/day 20.0a 19.5a 18.4b 0.32Average daily gain, lb 3.04 3.05 2.98 0.10Feed:gain 6.55 6.39 6.17 0.26

Hot carcass weight, lb 675 669 672 9.4Dressing percentage2 61.5 61.5 61.5 0.1Ribeye area, in2 12.8 12.8 12.7 0.2Fat thickness, in 0.40 0.39 0.37 0.02Kidney, pelvic & heart fat, % 2.2 2.2 2.2 0.05Liver abscesses, % 0.5e 4.2f 1.0e 1.1Yield grade 1, % 18 16 11 3.0Yield grade 2, % 38a 43a,b 50b 3.6Yield grade 3, % 41 39 35 3.9Yield grade 4 & 5, % 3 2 4 2.0Marbling scoreg Sl79 Sl82 Sl77 6.3USDA Prime, % 0.5 1 0 0.46USDA Choice, % 47 44 45 4.4USDA Select, % 47 50 48 3.8USDA Standard, % 5 5 7 1.4Dark cutters, % 0 0.5 0 0.3

1Shrunk weight = hot carcass weight ÷ common dressing percent of 64.05%.2Dressing percent = hot carcass weight ÷ live weight before shrink. a,bMeans within same row without a common superscript differ (P<0.05).c,dMeans within same row without a common superscript differ (P<0.01).e,fMeans within same row without a common superscript differ (P<0.10).gSl = Slight.


1South Central Area Extension Office, Hutchinson.2Southeast Area Extension Office, Chanute.

91


EFFECT OF COOKED MOLASSES TUBS ONPERFORMANCE AND HEALTH OF NEWLY

RECEIVED STOCKER CALVES

S. I. Paisley 1, G. L. Stokka, and F. K. Brazle2

Summary

Eight paired comparisons conducted atthree field sites with 1059 newly-receivedlightweight stocker calves were used todetermine the effect of free-choice cookedmolasses tubs designed for receiving cattleon 28-day receiving period performance,percentage of cattle treated for respiratorydisease, and death loss. At all sites, cattlereceived similar management with the excep-tion that cooked molasses tubs were added tohalf of the pens immediately following initialprocessing. Weight gains were similar(P=0.36) for cattle with or without access totubs (43 and 38 lb, respectively). The addi-tion of tubs also did not affect the number ofcattle treated (P=0.48) or percent death loss(P=0.61); however, there was a numericaldecrease in death loss for cattle with accessto tubs (2.7 vs 1.8%). Tub consumption(0.245 lb/day) based on beginning andending weights of the tubs, was below thedesired level of 0.5 lb/day. Low tub con-sumption may have compromised any poten-tial for improved performance or overallhealth response for cattle offered free accessto cooked molasses tubs.

(Key Words: Receiving, Cattle, CookedMolasses Tubs.)

Introduction

A recent Kansas survey estimated that65% of cattle entering Kansas originate inthe Southeastern U.S. Additionally, morethan 75% of stocker operators keep newly

received cattle in confinement for a mini-mum of 7 days. Feed intake by these stressedcalves is low, creating short- term nutritionaldeficiencies that could affect immune func-tion and increase susceptibility to disease.However, few operations adjust rations forlow feed consumption during this period.Providing additional vitamins and mineralsmay reduce morbidity, depending on previ-ous nutritional status. Our objective was todetermine if adding Rangeland Health CareProvider Stress Tubs (Farmland Industries,Inc.) to pens of newly-received cattle wouldimprove receiving period weight gainsand(or) reduce morbidity.


Eight paired comparisons were con-ducted on three producer sites across Kansasbetween November 4, 1999 and February 16,2000. Receiving periods ranging from 27 to32 days. In all cases, cattle arrived on thesame day and were randomly assigned to twopens. One of the pens received free-choiceaccess to vitamin and trace mineral-fortifiedcooked molasses tubs provided by FarmlandIndustries, Inc. Tubs were placed with cattleimmediately after initial processing at a rateof no more than 20 head/tub, with tubsplaced throughout the pen. Health programsdiffered slightly across sites, but cattle withor without tubs received similar managementat each location.

To determine whether providing StressTubs improved cattle’s ability to respond todisease, performance data for each pen were


92

further divided into two groups: 1) cattle thathad never been treated for respiratory dis-ease, and 2) cattle treated at least once forrespiratory disease.


Cattle without access to Stress Tubs wereslightly heavier (P=0.17; Table 1) than steersreceiving tubs (433 vs 415 lb). This differ-ence was maintained throughout the feedingperiod, and final weights of cattle withouttubs tended (P=0.07) to be heavier than thosewith access to tubs. Total weight gain anddaily gains were similar (P$0.36) for bothgroups, although daily gains were numeri-cally higher for cattle receiving tubs (1.28 vs1.46 lb/day). Morbidity and death loss wassimilar (P$0.22) for cattle with or withoutaccess to tubs. Daily supplement intakeswere below the recommended 0.5 lb/day,despite an adequate number of tubs and un-limited access. Due to site difference ininitial weights, tub intakes on a percent BWbasis are also reported. Additional work isneeded to determine if achieving desiredintakes would produce a greater response inanimal performance and decreased morbid-ity.

Performance and health differences ateach site mainly reflect the type of cattlepurchased, management prior to arrival, andenvironmental conditions during the receiv-ing period. Initial weights were different(P<0.01; Table 2) for each site. Site 1 pur-chased heavier calves from a regionalsalebarn. Sites 2 and 3 purchased lightercalves from the Southeastern U.S. Weightgain during the receiving period was similar(P=0.84) for all three sites, resulting in dif-ferent (P<0.01) final weights. Among sites,total number of cattle treated, or overallmorbidity, bordered on significance(P=0.08); however, there were differences intreatment duration among sites. Percentagesof cattle treated only once were similar(P>0.05) for Sites 1 and 3, and both werelower (P<0.05) than Site 2. Percentage ofcattle treated twice were lower (P<0.05) forSite 3 than Site 2, while Site 1 was interme-diate. Although there were no differences(P=0.20) in percentages of cattle treated threetimes, Sites 1 and 2 had the lowest percent-

age of chronics with 0 and 2%, respectively.Both were lower (P<0.05) than Site 3. Fi-nally, death loss was lower (P<0.05) at Site2 than Site 3, with Site 1 intermediate. Thegreater number of chronics and higher deathloss associated with Site 3 may be partiallyattributed to the lighter weights of cattle atthis site, as well as the fact that many of thecattle received at Site 3 were intact malesthat were castrated during initial processing.

Tub intakes by site show that only Site 1achieved the recommended intake of 0.5lb/day. Site 2 (0.31 lb/day) and Site 3 (0.11lb/day) tub intakes were considerably lowerthan target. At all sites, tubs were placednear feed and water and at the recommendedrate of not less than 1 tub per 20 steers.Because purchased steers were used at allthree sites, previous exposure to molassestubs is not known. Additional factors thatcould have affected tub intake include calfsize and origin (Sites 2 and 3 purchasedpredominately lighter calves from Southeast-ern U.S.), as well as differences in receivingmanagement.

To determine whether access to thecooked molasses tubs influenced the ani-mals’ ability to handle a disease challengeand respond to treatment, data from each penwas further divided between: 1) cattle thathad never been treated and 2) cattle that hadbeen treated a minimum of one time (deadsremoved). There were no interactions(P$0.50) between treatment history andaccess to cooked molasses tubs; however,there was a site by treatment history interac-tion for all performance variables, so site-specific means are presented in Table 3.

Site means broken down by treatmenthistory indicate that health managementstrategies may have been different for Site 1as compared to Site 2 and 3. Receivingperiod weight gain for cattle treated at leastonce was considerably lower (P<0.05) at Site1 than the other two sites, suggesting thatdisease exposure may have been more seri-ous at Site 1. Actual within-pen means ateach site (not shown) suggest that treatedcattle at Site 1 with access to the tubs lostless weight than treated cattle without tubs(based on only 1 rep); however, this trend


93

was not evident at Sites 2 and 3. Our resultssuggest that management and environmentplay a big role in an animal’s ability to re-

cover from disease, and do not rule out thepossibility that nutritional supplements mayalso play a role in overall health.

Table 1. Receiving Health and Performance Data of Cattle With or Without CookedMolasses Tubs

Item No Tubsa Stress Tubs SE P-value

Number, deads in (pens) 532 (8) 527 (8)

Initial wt, lbb 433 415 6.1 0.17

Final wt, lbc 471 459 2.5 0.07

Receiving period wt gain, lbd 38 43 3.0 0.36

Daily gain, lb/day 1.28 1.46 0.113 0.38

Observed sickness, %

Total treated 36.7 36.7 0.77 0.48

Treated once (1X) 24.1 26.1 1.88 0.53

Treated twice (1X not included) 5.4 4.2 0.52 0.25

Treated 3X (1 and 2X not included) 2.4 2.0 0.54 0.65

Chronics (treated more than 3X) 2.0 3.4 0.55 0.22

Deads 2.7 1.8 1.00 0.61

Daily tub intake, lb/head -- 0.245 -- --

% BW -- 0.075 -- --aLeast squares means using pen as the experimental unit.bTreatment by site interaction P=0.02.cFinal weight calculated using an unshrunk liveweight minus a 4% pencil shrink.dReceiving period for sites 1, 2 and 3.


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Table 2. Receiving Health and Performance Data of Cattle by Site

Trial Locationa OverallItem Site 1 Site 2 Site 3 SE P-valueNumber, deads in (pens) 107 (2) 445 (8) 507 (6)Initial wt, lbb 533 414 325 2.4 <0.01Final wt, lbc 570g 456f 368e 5.4 <0.01Receiving period wt gain, lbd 39 42 40 2.9 0.84Daily gain, lb/day 1.45 1.45 1.21 0.096 0.14Observed sickness, %Total treated 29.0 43.1 39.4 3.00 0.08 Treated once (1X) 20.6e 31.9f 22.9e 1.55 <0.01 Treated twice (1X not included) 4.7ef 7.6f 2.2e 0.72 <0.01 Treated 3X (1 and 2X not included) 2.8 0.9 3.0 0.94 0.20 Chronics (treated more than 3X) 0e 2.0e 6.2f 1.06 0.02 Deads 0.9ef 0.7e 5.1f 1.10 0.03Daily tub intake, lb/head 0.54 0.31 0.11 – -- % BW 0.107 0.080 0.038 – --

aLeast squares means using pen as the experimental unit .bTreatment by site interaction, P=0.02.cFinal weight calculated using an unshrunk liveweight minus a 4% pencil shrink.dReceiving periods ranged from 27 to 32 days for sites 1, 2, and 3.e,f,gMeans within a row with different superscripts differ (P<0.05).

Table 3. Receiving Health and Performance Data of Cattle by Treatment History andSite

Site 1 Site 2 Site 3Item Health

yTreated

Healthy TreatedHealthy Treated SE

Number (groups)a 76 (2) 31 (2) 253 (8) 192 (8) 307 (6) 200 (6)Initial wt, lb 526g 550g 417f 410f 339e 302d 5.6

Final wt, lbb 581h 543g 461f 447f 391e 324d 6.2Weight gain, lb 57g -4d 44fg 37f 51g 19e 5.3

Daily gain, lb/day 2.09g -0.14d 1.55fg 1.29f 1.54fg 0.60 e 1.70Day of 1st treatmentc 0 8.7d 0 7.7d 0 12.7e 0.81

aData analyzed using group means for healthy and treated cattle within each pen.bFinal weight calculated using an unshrunk liveweight minus a 4% pencil shrink.cUpon arrival, cattle at Site 3 received metaphylactic treatment using tilmicosin phosphate.d,e,f,g,hMeans within a row with different superscripts differ (P<0.05).


1Sincere apprec iation is expressed to the National Cottonseed Products Association for financialsupport.

95


USING A MIXTURE OF COTTONSEED HULLS AND COTTONSEED MEAL TO REPLACE ALFALFA HAY IN

DIETS FOR STRESSED FEEDER CALVES1

D. A. Blasi, J. S. Drouillard, T. B. Farran,R. D. Hunter, S. P. Montgomery, J. J. Sindt

Summary

One 28-day receiving experiment wasconducted using 625 exotic × British crossheifers to evaluate growth performance andmorbidity on receiving diets that containedeither alfalfa hay or a pellet composed of65% cottonseed hulls and 35% cottonseedmeal as the roughage source. Heifers fed thecotton byproduct pellet consumed more feed(P<0.01) but tended to be less efficient thanthose fed alfalfa hay. Daily gain was compa-rable between diets (P>0.05), and the per-centages of heifers diagnosed, treated, orretreated for respiratory disease were similar.

(Key Words: Cottonseed Hulls, ReceivingCattle, Health.)

Introduction

Typically, feed intake of stressed feedercalves is low and extremely variable follow-ing transportation and introduction into areceiving facility. Adequate energy intake iscritical for mounting an effective immuneresponse. Consequently, rations that are fedduring the receiving period must be palat-able and fortified with high levels of crudeprotein, energy, minerals, and vitamins.Furthermore, a roughage source that ispalatable and promotes ruminal health iscritical throughout the transition to a feedlotdiet. Our objective was to compare thegrowth performance and morbidity/mortalityrates of stressed calves fed receiving dietscontaining alfalfa hay or a mixture of cotton-seed hulls and cottonseed meal.


Six hundred twenty five crossbred heifersaveraging 448 lb were fed receiving dietscontaining either alfalfa hay or a mixture ofcottonseed hulls and cottonseed meal. Calveswere purchased from sale barns in Kentuckyand Tennessee and transported to the KSUBeef Cattle Research Center in Manhattan.They were placed into a large pen on arrival,given free access to long-stem prairie hayand water, and processed within 24 hours ofarrival. Weight and rectal temperature wererecorded, and heifers were given Cydectin®

pour-on, Fortress-7®, a Ralgro® implant anda metaphylactic dose of Micotil® at 1.5 mlper 100 lb body weight. They were allottedrandomly to their respective treatments andplaced into one of 12 pens of 48 to 55 headeach. A second dose of Fortress-7 was given12 to 14 days after initial processing.

Diets are shown in Table 1. Heifers werefed their respective diets once daily, adlibitum. After the 28-day receiving trial allheifers were fed a common diet to equalizeruminal fill between treatments. Feed con-sumption and weight gain were monitoredthroughout the receiving period.

Animals that exhibited clinical signs ofrespiratory disease were identified eachmorning and were treated for respiratorydisease if clinical signs were accompaniedby a rectal temperature >103°F, or if theyexhibited clinical signs on 2 consecutivedays. The initial respiratory disease treatmentwas a subcutaneous injection of Micotil at 1.5 ml


96

per 100 lb body weight. Heifers were re-turned to their original pen following treat-ment. When necessary, calves were retreatedafter 48 hours, regardless of rectal tempera-ture. The third-time treatment was a combi-nation of 6 ml/100 lb body weight LA® 200and 5 ml/100 lb body weight Tylan® 200,administered intramuscularly.


Table 2 summarizes the performance ofheifers during the 28-day receiving experi-ment. Heifers fed the cotton byproduct pelletconsumed more feed (P<0.01) but tended tobe less efficient than the heifers that were fedalfalfa hay (5.61 vs 4.78 lbs of feed/lb gain).Whether calculated on a deads in or deadsout basis, daily gain was comparable between

diets. The percentage of heifers diagnosedand treated, or retreated, for respiratorydisease were similar.

Our results indicate that a pelleted cot-tonseed byproduct (65% cottonseed hulls and35% cottonseed meal) is comparable toalfalfa hay in receiving diets. The bulkdensity of cottonseed hulls is low and han-dling is therefore cumbersome. However,blending hulls with cottonseed meal andpelleting offers distinct advantages in termsof transportation, ease of handling, andprotein content. When taken together, thesefactors improve the marketing radius of thesebyproducts. Therefore, use of cottonseedbyproducts may be a viable alternative toalfalfa in receiving diets.

Table 1. Composition of Receiving Diets (100% Dry Basis)

Ingredient, %Cottonseed Hulls/

Meal Pellet Alfalfa HayFlaked corn 44.65 42.08Alfalfa hay 40.00Pelleted cottonseed hulls/meala 40.00Cottonseed meal 5.31 8.00Molasses 6.00 6.00Vitamin premix 4.04 3.92

Nutrient Analysis Dry matter, % 84.7 83.5 Crude protein, % 15.6 15.3 ADF, % 19.4 22.1 Calculated NEg, Mcal/lb 0.51 0.47 Fat, % 3.45 2.46 Phosphorus, % 0.46 0.36 Potassium, % 1.40 1.63 Copper, ppm 10.3 16.8 Zinc, ppm 82.5 89.8 Total starch, % 48.1 41.1aContained (dry matter basis) 65% cottonseed hulls and 35% cottonseed meal; nutrientcomposition: 22.0% crude protein, 34.3% crude fiber, 48.6% ADF, 0.21 Mcal/lb NEg,0.18% calcium, and 0.64% phosphorus.


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Table 2. Performance of Feeder Heifers Fed Receiving Diets Containing Alfalfa Hayor Cottonseed Hulls (65%)/Cottonseed Meal (35%) Pellets as Sources ofRoughage

ItemPelleted Cottonseed

Hull/Meal Alfalfa Hay Pa

No. pens 12 12

No. heifers 313 312

Daily Gain, lb/day

Deads in basis 2.15 2.22 0.83

Deads out basis 2.64 2.52 0.72

Dry Matter Intake, lb/day 11.8 10.7 <0.01

Feed:Gain

Deads in basis 5.61 4.78 0.27

Deads out basis 4.52 4.23 0.54

Mortality 3.2 1.9 0.38

Pulled, % 48.8 45.3 0.44

Treated, % 35.7 35.2 0.89

Retreated, % 26.2 23.2 0.38

aProbability level that the difference is due to chance.


1Minnesota Corn Processors Inc., Marshall, MN.

98


ALFALFA HAY AND WET CORN GLUTEN FEED LEVELSIN STEAM-FLAKED CORN FINISHING DIETS

J. J. Sindt, J. S. Drouillard, J. N. Pike,S. P. Montgomery, C. M. Coetzer, T. B. Farran,

T. J. Kessen, and R. T. Ethington 1

Summary

A 153-day finishing experiment wasconducted using 631 heifers to determineoptimum alfalfa hay and wet corn glutenfeed (WCGF) combinations in steam-flaked,corn-based diets. Diets contained either 2 or6% alfalfa hay and 25, 35, or 45% WCGF(dry basis). Performance was similar(P>0.16) for cattle fed 2 or 6% alfalfa hay.Gain efficiencies (P<0.05) and fat thickness(P<0.10) declined linearly with increasingamounts of WCGF. For heifers fed 2%alfalfa hay, ribeye area increased with in-creasing dietary WCGF. However for heif-ers fed 6% alfalfa hay, ribeye area decreasedwith increasing dietary WCGF. Liver ab-scesses were lowest for heifers fed 35%WCGF. Alfalfa hay fed at 2% of diet drymatter is sufficient for steam-flaked corndiets containing 25, 35 or 45% WCGF.

(Key Words: Wet Corn Gluten Feed, Steam-flaked Corn, Finishing Cattle.)

Introduction

Wet corn gluten feed (WCGF) has beenincorporated into many feedlot diets in theNorthern plains, usually as an energy re-placement for grain, and has effectivelyreplaced 30% of steam-flaked corn in finish-ing diets. However, a large fraction ofWCGF is fermentable fiber. Due to theircost per unit of energy and potential toshrink, roughages such as alfalfa hay areburdensome in finishing diets. We hypothe-sized that WCGF could be utilized as both anenergy and roughage source to replace a

portion of both alfalfa hay and steam-flakedcorn.


Six hundred thirty-one crossbred heifersweighing 626 lb were used in a 153-dayfinishing experiment. Heifers were ran-domly allocated to pens and stratified byweight to six treatments (2 pens per diet, 48to 58 heifers per pen). The steam-flakedcorn-based diets consisted of 2 or 6% alfalfahay and either 25, 35, or 45% WCGF (drybasis) in a 2 × 3 factorial arrangement oftreatments. Diet compositions are shown inTable 1.

Heifers were implanted with Synovex®Con day 1 and were adapted to the final finish-ing diets within 21 days. Cattle were offeredad libitum access to diets once daily. Finalfinishing diets provided 300 mg Rumensin®,90 mg Tylosin®, and 0.5 mg MGA® perheifer daily. On day 56 heifers were re-implanted with Synovex®

Plus. Unconsumedfeed was collected, weighed, analyzed fordry matter content, and subtracted from theoriginal feed offered to determine actual feedintakes.

Average daily gain and gain efficiencieswere calculated using final weights estimatedas hot carcass weight divided by a commondressing percentage (63.3%).


Feeding performance and carcass charac-teristics are summarized in Table 2. Dry


99

matter intake, average daily gain and gainefficiencies were similar (P>0.16) for cattlefed 2 or 6% alfalfa hay, which suggest thatfeeding 2% alfalfa hay is sufficient roughagefor cattle fed these diets. Dry matter intaketended to increase (P=0.19) as the level ofWCGF increased; however, average dailygain was not different (P>0.70). This re-sulted in poorer (P<0.05) feed efficiencies asdietary WCGF increased. We observed aninteraction (P<0.10) between levels of alfalfahay and levels of WCGF for ribeye area. Forheifers fed 2% alfalfa hay, ribeye area in-creased with increasing WCGF. Howeverfor heifers fed 6% alfalfa hay, ribeye areadecreased with increasing WCGF. Fat thick-

ness decreased linearly (P<0.10) as the levelof WCGF increased, suggesting a decline indietary energy with additional WCGF.Although the occurrence of liver abscesseswas low (averaging 2.7%), it was lowestwhen 35% WCGF was fed, implying that amore suitable rumen environment was main-tained.

Heifer performance was not affected byreducing alfalfa hay levels to 2% of diet drymatter. Gains were less efficient and car-casses were leaner with increasing levels ofWCGF. Alfalfa hay and wet corn glutenfeed levels created an interaction for ribeyearea.

Table 1. Composition of Experimental Diets (% of diet dry matter)

Level of Wet Corn Gluten Feed

2% Alfalfa Hay 6% Alfalfa Hay

Ingredient 25% 35% 45% 25% 35% 45%

Flaked corn 63.6 55.1 46.3 60.4 51.6 42.4

Wet corn gluten feed 23.5 33.2 43.1 23.6 33.3 43.2

Alfalfa hay 1.9 1.9 2.0 5.8 5.8 5.9

Tallow 3.0 3.0 3.0 3.0 3.0 3.0

R-T-MGA premix1 2.6 2.6 2.5 2.6 2.5 2.6

Soybean meal 2.0 1.0 - 1.4 0.7 -

Urea 1.0 0.9 0.8 1.0 0.9 0.8

Limestone 1.6 1.6 1.6 1.5 1.5 1.5

Sodium chloride 0.3 0.3 0.3 0.3 0.3 0.3

Potassium chloride 0.4 0.3 0.3 0.3 0.3 0.2

Vitamin/trace mineral premix2 0.1 0.1 0.1 0.1 0.1 0.1

Nutrient, analyzed

Dry matter, % 69.3 64.0 59.3 69.2 63.9 59.3

Crude protein, % 14.7 15.0 15.2 14.7 14.9 15.3

Calcium, % 0.7 0.7 0.7 0.6 0.6 0.7

Phosphorus, % 0.3 0.3 0.4 0.3 0.3 0.41R-T-MGA premix formulated to provide: 300 mg/heifer/day Rumensin, 90 mg/heifer/day Tylosin,and 0.5 mg/heifer/day MGA.2Vitamin/trace mineral premix formulated to provide (total diet dry matter): 1,000 IU/lb Vitamin A,0.13 ppm cobalt, 0.63 ppm iodine, 60 ppm manganese, 0.25 ppm selenium, 60 ppm zinc, 10 ppmthiamin, 10 ppm copper, and 2 ppm iron.


100

Table 2. Finishing Performance and Carcass Characteristics

Level of Wet Corn Gluten Feed

2% Alfalfa Hay 6% Alfalfa Hay

Item 25% 35% 45% 25% 35% 45% SEM

No. of heifers 105 105 104 105 106 106

Initial weight, lb 628 625 630 623 626 625 12.3

Final weight, lb 1109 1108 1110 1105 1114 1104 20.1

Dry matter intake, lb/day 16.7 17.5 17.3 17.2 17.9 17.6 0.37

Average daily gain, lb 2.55 2.55 2.55 2.56 2.58 2.51 0.049

Feed:gaina 6.54 6.85 6.80 6.67 6.94 6.99 0.015

Hot carcass weight, lb 672 673 672 676 683 662 12.6

Dressing percentage 63.1 63.3 63.1 63.7 63.8 62.5 0.38

Ribeyeb area, in2 12.5 12.5 12.9 12.6 12.5 12.2 0.16

KPHc, % 2.3 2.3 2.2 2.4 2.5 2.3 0.11

Fat thicknessd, in 0.48 0.47 0.43 0.48 0.50 0.45 0.018

USDA yield grade

Yield grade 1, % 9 10 10 6 7 6 2.6

Yield grade 2, % 32 27 42 34 32 37 6.0

Yield grade 3, % 46 56 44 50 48 47 5.3

Yield grade 4 & 5, % 14 5 14 8 10 10 3.8

Marbling scoree Sm20 Sm20 Sm14 Sm65 Sm24 Sm29 20.5

USDA quality grade

Prime & Choice, % 59 55 57 68 60 60 8.6

Select, % 39 43 40 30 38 37 8.7

Standard, % 2 2 1 1 2 3 1.7

Dark cutters, % 0 0 1 0 0 0 0.4

Liver abscesses f, % 2.7 1.9 2.8 4.7 0.9 2.9 .76aWet corn gluten feed level, linear effect (P<0.05).bAlfalfa hay × wet corn gluten feed interaction (P<0.10). cKPH = Kidney, pelvic & heart fat. dWet corn gluten feed level, linear effect (P<0.10).eSm = Small.fWet corn gluten feed level, quadratic effect (P<0.05).


1Cargill Corn Milling, Blair, NE.

101


ADDITION OF UREA TO FINISHING CATTLE DIETS CONTAINING STEAM-FLAKED CORN AND

WET CORN GLUTEN FEED

S. P. Montgomery, J. S. Drouillard, J. J. Sindt, T. B. Farran, N. J. Pike, C. M. Coetzer, H. J. LaBrune,

A. M. Trater, R. D. Hunter, and R. A. Stock 1

Summary

Three hundred thirty-nine crossbred beefheifers were used in a 74-day finishing studyto evaluate effects of adding 0.5% urea tofinishing diets containing steam-flaked cornand 34% (dry basis) Sweet Bran® wet corngluten feed (WCGF). Diets were fed oncedaily ad libitum. Urea addition tended(P<0.06) to increase finishing average dailygain, to improve (P<0.12) feed efficiency,and to increase (P<0.06) fat thickness. Heif-ers fed urea had a lower percentage (P<0.03)of carcasses grading USDA Choice. Thisstudy suggests that finishing diets containinga combination of steam-flaked corn andWCGF may benefit from addition of urea asa source of supplemental ruminally availablenitrogen.

(Key Words: Wet Corn Gluten Feed, Urea,Finishing.)

Introduction

Cattle consuming corn-based finishingdiets normally require supplementalruminally available nitrogen sources such asurea or soybean meal to optimize ruminalstarch fermentation. Because WCGF con-tains a degradable intake protein fractionsimilar to that of soybean meal, our objectivewas to determine if adding urea to dietscontaining WCGF would result in furtherperformance improvements.


Three hundred thirty-nine beef heifersaveraging 804 lb were used in a randomizedcomplete block design experiment. Heiferswere blocked by previous nutritional regi-men, and treatments were randomly assignedto pens containing four to seven heifers perpen, with 27 pens per treatment. Treatments(Table 1) consisted of steam-flaked cornfinishing diets containing 34% Sweet BranWCGF with or without 0.5% urea (dry mat-ter basis). Diets were fed once daily adlibitum for 74 days, and then heifers wereslaughtered and carcass data were obtained.


Performance data was shown in Table 2.Average daily gains (P<0.06) and feed effi-ciencies (P<0.12) tended to be improvedwith urea supplementation. Backfat thicknessalso tended (P<0.06) to be increased withurea supplementation. In spite of the ten-dency for increased 12th rib fat, the percent-age of carcasses grading USDA Choice orPrime was greater for cattle fed no urea. Weconclude that steam-flaked corn finishingdiets containing 34% WCGF (dry matterbasis) may benefit from the addition of aruminally available nitrogen source such asurea.


102

Table 1. Experimental DietsTreatments

Ingredients No Urea Urea----------% of Dry Matter---------------

Steam-flaked corn 55.8 55.3Alfalfa hay 6.0 6.0Wet corn gluten feed 33.8 33.8Tallow 2.1 2.1Urea - 0.5Limestone 1.6 1.6Sodium chloride 0.3 0.3Potassium chloride 0.3 0.3Vitamin/trace mineral premixa 0.1 0.1Crude protein, analyzed 14.9 16.1

---------- Per Head Dailyb ---------------Rumensin® 300 mg 300 mgTylang 90 mg 90 mgMelengestrol acetate 0.5 mg 0.5 mg

aVitamin/trace mineral premix formulated to provide (total diet dry matter): 1,200 IU/Ibvitamin A, 0. 1 ppm cobalt, 20 ppm copper, 0.5 ppm iodine, 50 ppm manganese, 0.2 ppmselenium, and 50 ppm zinc. bRumensin/Tylan/Melengestrol Acetate supplement fed at 0.44lb per head per day (dry matter basis).

Table 2. Effects of Urea on Performance and Carcass CharacteristicsTreatment

Item Control Urea SEM P-valueNo. of heifers 167 172Initial weight, lb 806 802 6.4 0.71Final weight, lba 1058 1066 8.4 0.52Dry matter intake, lb/day 20.3 20.6 0.20 0.28Average daily gain, lb 3.41 3.56 0.05 0.06Feed:gain 5.95 5.78 0.07 0.12Hot carcass weight, lb 670 676 5.3 0.52Dressing percentageb 60.8 60.9 0.2 0.68Ribeye area, in2 12.5 12.5 0.14 0.93Fat thickness, in 0.40 0.44 0.01 0.12Kidney, pelvic & heart fat, % 2.2 2.2 0.03 0.15Liver abscesses, % 3.6 2.3 1.3 0.52Yield grade 1, % 13 11 2.5 0.54Yield grade 2, % 40 40 3.8 0.96Yield grade 3, % 42 43 3.8 0.83Yield grade 4 & 5, % 5 6 2.4 0.50Marbling scorec Sm22 Sm14 7.5 0.45USDA Prime, % 3 4 1.2 0.57USDA Choice, % 64 51 3.7 0.03USDA Select, % 31 40 3.7 0.10USDA Standard, % 1 4 1.1 0.15Dark cutters, % 1 1 0.8 0.92

aFinal weight = hot carcass weight ÷. common dressed yield of 63.36%. bDressing percent= hot carcass weight ÷ live weight before shrink. cSm = Small.


1Department of Statistics.

103


COMBINATIONS OF WET CORN GLUTEN FEED AND STEAM-FLAKED CORN IN FINISHING CATTLE DIETS:

EFFECTS ON ACID-RESISTANT E. COLI AND COLIFORMS, VFA PROFILES AND PH

J. J. Sindt, J. S. Drouillard, H. Thippareddi, R. K. Phebus, D. L. Lambert, T. B. Farran, S. P. Montgomery,

H. J. LaBrune, and J. J. Higgins 1

Summary

Finishing beef steers (615 head) wereused in a 152-day experiment to evaluate theeffects of feeding 80:0, 60:30 or 30:60 ratios(dry basis) of steam-flaked corn and wet corngluten feed (WCGF, 30WCGF, 60WCGF)on acid-resistant E. coli and coliforms. Ondays 114 to 118 ruminal and fecal sampleswere collected from 180 steers and analyzedfor pH, VFA, and total and acid-resistantEscherichia coli (E. coli) and coliforms.Ruminal (P=0.13) and fecal (P=0.10) VFAtended to decrease linearly as CGFincreased. Consequently, there was a corre-sponding numerical linear increase inruminal pH and a significant linear increasein fecal pH (P<0.05). Total and acid-resistantE. coli and coliforms, however, were notaffected (P>0.10) by dietary treatment.

(Key Words: E. coli, Food Safety, FinishingCattle.)

Introduction

Recent research has indicated that addinghay to the diets of grain-fed cattle 4 daysprior to slaughter can impact fermentationpatterns and alter the acid-resistant microbialpopulation in the feces, specifically E. coli.Feedlot diets typically contain a large portionof starch from grain sources. In highlyprocessed grains, the rumen is the main siteof starch digestion and volatile fatty acidproduction. However, some of this grainstarch passes to the lower gastrointestinaltract and is fermented in the cecum and colon.This passage of starch and the resulting acid

production may cause E. coli to developacid-resistance.

Wet corn gluten feed (WCGF) is a highenergy, low-starch feedstuff that has beenused as an energy source in high-grain diets.We hypothesized that the fibrous, low-starchcharacteristics of WCGF, could be utilized tomanipulate ruminal and fecal organic acidconcentrations, thus preventing developmentof acid resistance among coliform bacteria.


Six hundred fifteen crossbred beef steers(average wt 649 lb) were fed diets containingeither 80:0 (WCGF), 60:30 (30WCGF), or30:60 (60WCGF) ratios of steam-flaked cornand WCGF throughout a 152-day finishingexperiment. Diet compositions are shown inTable 1. Steers were blocked by previoustreatment and randomly allocated to the threediets (four pens per diet with 48 to 53 steersper pen). Rumen fluid (collected viarumenocenteses) and feces were obtainedfrom 180 steers (three animals per pen oneach sampling day) on days 114 to 118.Samples of rumen fluid and feces wereincubated for 1 hour in citric acid/sodiumphosphate buffer solutions at pH 2, 4, and 7for determination of total and acid-resistantE. coli and coliforms. After incubation thesamples subjected to the pH 2 and 4 bufferswere neutralized with 1 M NaOH solutionand placed on ice. Samples were seriallydiluted, plated onto Petrifilm™ plates, incu-bated at 37°C for 24 to 48 hours, and enu-merated.


104


Ruminal volatile fatty acid (VFA) con-centration and fecal VFA concentrationstended to decrease linearly as WCGF wasadded to the diet (Figure 1). Consequently,there was a corresponding linear increase forruminal and fecal pH (P<0.05) (Figure 2).Despite the shift in fermentation patterns, E.coli and coliform counts in ruminal fluid andfecal samples of cattle fed different dietswere similar (P>0.10) at pH buffer treat-ments 2, 4, and 7 (Table 2). This suggeststhat ruminal and fecal acid concentrations,which were all above pH 6, were not acidicenough for coliform bacteria to develop acid

resistance. The molar proportion of ruminaland fecal acetate increased linearly (P<0.05),and the molar proportion of ruminal andfecal propionate decreased linearly (P<0.05)as WCGF was added to the diet, suggestingthat fermentation of fiber replaced that ofstarch in both the rumen and hindgut as moreWCGF was fed (Figures 3 and 4).

Addition of WCGF to finishing dietsaltered VFA concentrations and increasedpH; however, no differences were observedwith respect to numbers of E. coli, totalcoliforms, acid-resistant E. coli, or acid-resistant coliforms.

Table 1. Composition of Experimental Diets (% of diet dry matter)

Dietary Wet Corn Gluten FeedIngredient 0% 30% 60%Flaked corn 81.60 58.37 30.21Alfalfa hay 6.71 - 6.97Molasses 3.72 - -Tallow 2.01 2.05 2.09Wet corn gluten feed - 28.64 58.51Soybean meal 2.83 1.44 -Urea 1.21 0.79 0.36Limestone 1.18 1.28 1.39Sodium chloride 0.29 0.29 0.30Potassium chloride 0.04 0.02 -Ammonium sulfate 0.19 0.10 0.10Calcium phosphate 0.12 0.06 0.06Vitamin/trace mineral premix1 0.10 0.10 0.10

Nutrient, analyzedDry matter, % 83.4 65.0 53.0Crude protein, % 14.9 15.2 15.4Calcium, % 0.66 0.70 0.75Phosphorus, % 0.29 0.35 0.41Thiamin, ppm - 7.5 15Copper, ppm 8.3 12.2 16.0

1Vitamin/trace mineral premix formulated to provide (total diet dry matter): 1,200 IU/lbvitamin A, 0.10 ppm cobalt, 0.52 ppm iodine, 50 ppm manganese, 0.25 ppm selenium, 50 ppmzinc, 30 grams/ton Rumensin®, and10 grams/ton Tylan®.


Table 2. Effects of Diet and Buffer Treatment on Ruminal and Fecal E. coli andColiforms

item .Rumen E. Coli

Buffer treatment

pH2pH4pH7

Rumen total coliformsBuffer treatment

pH2pH4pH7

Fecal E. coliBuffer treatment

pH2pH4pH7

Fecal total coliformsBuffer treatment

pH2pH4pH7

Figure 1.

140

120

loo

2 80

’ 60

40

20

0

Total Ruminal and Fecal VFA Concentrations of Cattle Fed 0, 30, or 60% WetCorn Gluten Feed.

105


6.8

6.6

6.4

6.2

6.0

5.8

5.6Ruminal pH Fecal pH ’

lOCGF q 30CGF q 6OCGF‘Linear effect of CGF (Pt05).

Figure 2. Ruminal and Fecal pH of Cattle Fed 0,30, and 60% Wet Corn Gluten Feed.

A c e t a t e +Propionate Butyrate

+; fis=g 2 0 ’

Linear effect of CGF (Pc.05).

10 - 1Am \

0 . d

0CGF 30CGF 60CGF.

Figure 3. Molar Proportions of Ruminal VFA of Cattle Fed 0, 30, or 60% Wet CornGluten Feed.

-Acetate +Propionate +Butyrate

80 -‘. 70’

s60t 5 0 ’tg 40’= 3 0 ’E

20 l

+

t of CGF (Pc.05).

OCCF 30CGF 60CGF

Figure 4. Molar Proportions of Fecal VFA of Cattle Fed 0,30, or 60% Wet Corn GlutenFeed.

106


IET n/a

IET n/a

IET n/a

IET n/a

IET n/a

IET n/a

IET n/a

IET n/a

IET n/a

IET n/a

IET n/a

107


INDEX OF KEY WORDS

Indexer’s note: The numbers refer to the first pages of each article that uses the listed key word.

Aging, 59AI, 15Alfalfa, 86Alfalfa Hay, 83Amino Acids, 74Antibody, 29Beef, 47, 59, 61, 64, 70Beef Cattle, 37Beef Demand, 20Beef Processors, 23Belt Grill, 52Biceps femoris, 55Blade Tenderization, 55Breeding Soundness, 1Buller Steer Syndrome, 34Bulls, 1Carcass, 67Carcass Characteristics, 70Carcass Traits, 26Cattle, 91Cattle Marketing, 23CIDR, 9Color, 59, 64Color Stability, 61Consumer Demographics, 20Contracts, 23Cooked Molasses Tubs, 91Cooking, 42, 45, 47Cottonseed Hulls, 95Cows, 9, 12Cutability Indicators, 67Digestibility, 80Digestion, 86E. coli, 103E. coli O157:H7, 42Electric Broiler, 52Embryo, 9Estrogen, 12

Exam, 1Fat Thickness, 70Feedlot, 26Finishing, 101Finishing Cattle, 98, 103Flint Hills Pastures, 34Food Safety, 20, 103Forced-Air Convection

Oven, 52Genetic Correlation, 1GnRH, 15Growing 83Growth Implant, 26Health, 95Health Concerns, 20Heat Penetration, 52Heifers, 15Heritability, 1Isoleucine, 77Leucine, 77Limit Feeding, 80, 83, 88Marketing Agreements, 23Meat, 45Methods, 45Metmyoglobin, 61MGA, 9, 15, 17Minerals, 31Native Grass, 31Nutrition, 31Ovulation, 9Passage Rate, 80, 86Passive Immunity, 29Pasture, 26PGF2", 15Phytoestrogen, 34Postmortem Aging, 55Postpartum Interval, 17Pregnancy Rate, 17

Pregnancy Rates, 12Progesterone, 12Protein, 31, 37Quality, 55Quality Grade, 67, 70Ralgro, 26Range, 37Receiving Cattle, 95Receiving, 91Reducing Activity, 61Repeatability, 47Requirements, 74Restructured Beef Steaks, 42Resynchronization of Estrus,

12Ribeye Area, 70Rumensin, 88Scrotal Circumference, 1Self-Feeding, 37Semimembranosus, 61Short Cycle, 17Soybean Hulls, 86Steam-flaked Corn, 98Steers, 26, 74, 77, 86Supplementation, 37Survival, 9Synchronization, 9, 15Temperature, 45Tenderness, 47, 55, 59Tylan, 88Urea, 101Vaccination, 29Valine, 77Vascular Infusion, 64Wet Corn Gluten Feed, 80,

83, 98, 101Yield Grade, 67


108

Notice

Kansas State University makes no endorsements, expressed or implied, of any commercial product. Trade names are used inthis publication only to assure clarity of communication.

Some of the research reported here was carried out under special FDS clearances that apply only to investigational uses atapproved research institutions. Materials that require FDA clearances may be used in the field only at levels and for the usesspecified in that clearance.


BIOLOGICAL VARIABILITY AND STATISTICAL EVALUATION OF DATA

The variability among individual animals in an experiment leads to problems in interpreting theresults. Animals on treatment X may have a higher average daily gain than those on treatment Y, butvariability within the groups may indicate that the difference between X and Y is not the result of thetreatment alone. You can never be totally sure that the difference you observe is due to the treatment,but statistical analysis lets researchers calculate the probability that such differences are from chancerather than from the treatment.

In some articles, you will see the notation "P<0.05." That means the probability that theobserved difference was due to chance is less than 5%. If two averages are said to be "significantlydifferent," the probability is less than 5% that the difference is due to change— the probability exceeds95% that the difference is true and was caused by the treatment.

Some papers report correlations — measures of the relationship between traits. Therelationship may be positive (both traits tend to get larger or smaller together) or negative (as one getslarger, the other gets smaller). A perfect correlation is either +1 or –1. If there is no relationship atall, the correlation is zero.

You may see an average given as 2.5 ± .1. The 2.5 is the average; .1 is the "standard error."That means there is a 68% probability that the "true" mean (based on an unlimited number of animals)will be between 2.4 and 2.6. "Standard deviation" is a measure of variability in a set of data. Onestandard deviation on each side of the mean is expected to contain 68% of the observations.

Many animals per treatment, replicating treatments several times, and using uniform animalsall increase the probability of finding real differences when they actually exist. Statistical analysisallows more valid interpretation of the results, regardless of the number of animals in an experiment.In the research reported herein, statistical analyses are included to increase the confidence you canplace in the results.

In most experiments, the statistical analysis is too complex to present in the space available.Contact the authors if you need further statistical information.

WEATHER DATA, 1999-2000

On the following page are graphs of the 1999 and 2000 Manhattan weather. They wereproduced by the Kansas State University Weather Data Library. The smooth line that starts in thelower left corner of each graph is the normal accumulated precipitation since January 1. The roughline starting in the lower left corner represents actual accumulated precipitation. A long horizontalsection of that line represents time during which no precipitation fell. A vertical section representsprecipitation. The other two smooth lines represent average daily high and low temperatures, and therough lines represent actual highs and lows.

These graphs are included because much of the data in this publication, especially data onanimal maintenance requirements and forage yields, can be influenced by weather. Weather graphshave been included in Cattlemen's Day publications since 1985.


Jul 9Day of Year

Oct25 Oec 18

8 0

G:

g60a

f 4 0

e

2 0

0

,60

J8tl28 Mar23 May16 oct25 [kc18

Summaries of Weather in Manhattan, KS, 1999 and 2000

.60

.!50

-40E-e.5

-3og15

B0.

-20

-10

- 0

109


110


ACKNOWLEGEMENTS

Listed below are individuals, organizations and firms that have contributed to this year’s beef researchprogram through financial support, product donations, or services. We appreciate your help!

ADM Milling Company, Decatur, IllinoisAlpharma Inc., Animal Health Division,

Fort Lee, New Jersey.American Angus Association,

St. Joseph, MissouriAmerican Simmental Association,

Bozeman, MontanaBayer Animal Health,

Shawnee Mission, KansasBayer Diagnostics, Terrytown, New YorkBoehringer Ingelheim Animal Health,

St. Joseph, MissouriCelera AgGen, Rockville, MarylandCustom Lettering and Graphics,

Manhattan, KansasBorck, Larned, KansasBrill Corporation, Norcross, GeorgiaCargill Corn Wet Milling Division,

Blair, NebraskaCargill Inc., Minneapolis, MinnesotaCargill Meat Sector, Minneapolis, MinnesotaCentral City Scale, Central City, NebraskaDow Agrosciences, Indianapolis, IndianaE.I. duPont de Nemours,

Wilmington, DelewareElanco Animal Health, Indianapolis, IndianaExcel Corporation, Wichita, KansasFarmland Industries, Kansas City, MissouriFarnam Companies, Inc., Phoenix, Arizona Fink Beef Genetics, Manhattan, Kansas Fort Dodge Animal Health, Fort Dodge, IowaFrisbie Construction, Gypsum, KansasGenomics FX, College Station, Texasibp, inc., Emporia, KansasInterAg, Hamilton, New ZealandIowa Limestone Company, Des Moines, IowaKansas Artificial Breeding Service Unit,

Manhattan, KansasKansas Beef Council, Topeka, KansasKansas Livestock Assn., Topeka, KansasKansas Corn Commission, Topeka, Kansas

Kansas Grain Sorghum Commission, Topeka, Kansas

Kansas Soybean Commission, Topeka, KansasKock Industries Feedlot, Wichita, Kansas Livestock and Meat Industry Council (LMIC),

Manhattan, KansasLONZA, Inc., Fair Lawn, New JerseyLyons Ranch, Manhattan KansasMerial Limited, Iselin, New JerseyMinnesota Corn Processors, Inc.,

Marshall, MinnesotaMohrlang Manufacturing, Brush, ColoradoMPSC, Inc., Eden Paririe, MinnesotaNational Cattlemen’s Beef Assn,

Greenwood Village, ColoradoNCBA Cattlemen’s Data Service

Greenwood Village, ColoradoNational Cottonseed Products Assn.,

Memphis TennesseeNational Farms, Cottonwood Falls, KansasNorth American Meat Processors Assn.

Reston, VirginiaOleen Brothers, Dwight, KansasSDK Labs, Hutchinson, KansasPfizer Animal Health, exton, PennsylvaniaPharmacia Animal Health,

Kalamazoo, MichiganRoss Industries, Midland, VirginiaS-Bar Ranch Feedlot, Sublette, KansasSchering-Plough Animal Health,

Kenilworth, New JerseySelect Sires, Plain City, OhioUSDA Food Safety Consortium,

Washington, DCUSDA, Cooperative State Research Education and Extension Service,

Washington, DCVetLife, Inc., Overland Park, KansasViskase Corp., Chicago, IllinoisWest Texas A&M University

Canyon, Texas


Kansas State University Agricultural Experiment Station and Cooperative Extension Service, Manhattan 66506SRP 873 March 2001It is the policy of Kansas State University Agricultural Experiment Station and Cooperative Extension Service that all persons shall have equal opportunity andaccess to its educational programs, services, activities, and materials without regard to race, color, religion, national origin, sex, age, or disability. Kansas StateUniversity is an equal opportunity organization. These materials may be available in alternative formats. 2.3 M


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