efficacy of pour-on dewormers on weight gain and fecal egg count in hawaiian stocker cattle jonathon...
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Efficacy of pour-on dewormers on weight gain and fecal egg count in
Hawaiian stocker cattle
Jonathon Beckett1, Tim Richards2, Craig Reinemeyer3
1Animal Science Department, Cal Poly State University, Kahua Ranch2, East
Tennessee Clinical Research3
What is a Parasite?
The Random House Dictionary defines it as an organism that lives on or within a plant or animal of a different species, from which it obtains nutrients.
Parasites of ConcernBunostomum phlebotomum (Cattle Hookworm)•Causes itching of the leg and feet• Irritate stomach and intestines• Feed on blood in the intestinal wall• Causes bloody, tar colored diarrhea
Fasciola hepatica (Common Liver Fluke)•Live in the bile ducts of the liver, and gallbladder• Animals experience anemia and decreased growth• Usually results in condemnation of the liver at slaughter
Strongyloides papillosus (Intestinal threadworm)•Most common in young calves• Causes intermittent diarrhea, loss of appetite, and weight
Parasites of ConcernCooperia spp (Cattle Bankrupt worm)•Lives in the Small Intestine•Animals exhibit poor utilization of feed, taking a long time to reach market weight
Ostertagia ostertagia (Brown Stomach Worm) •Affected cattle not only lose weight but often die• Cells damaged by the parasite are replaced by rapidly dividing cells that lack function•The most commonly found and economically important internal parasite
Toxocara vitulorum (Large Roundworm)•Live in the Small Intestine• Found especially in warm climates• can travel through the lung and cause pneumonia• Compete with host for food , causing diarrhea and weight loss
Clinical Parasitism
Diarrhea
Anemia
Rough hair coat
“Pot bellied” appearance
“Bottle jaw”
Less common
Subclinical Parasitism
Decreased milk production
Poor performance
More susceptible to disease
Infertility
Unthrifty
We Deworm Cattle For Only One Reason
FOR THE MONEY
Benefits of Deworming
Increased productivity
Increased efficiency
Better immune status
Increased breeding efficiency
Reduced pasture contamination
Importance of fecal egg counts?
Most commonly used technique Usefulness depends on its precision
and accuracy Requires knowledge of parasite biology
in area, experience with levels that are indicative of economic impact in a given situation
Importance of Larval Cultures
Very few parasitologist are able to differentiate between different genera of the parasite eggs
Nematodirus is only “easy one” Larval cultures let eggs hatch then the
worms are identified
Macrocyclic Lactones
Avermectins– Ivermectin (Ivomec)– Doramectin (Dectomax)– Eprinomectin (Eprinex– Look alikes– Generic
Milbemycins– Moxidectin (Cydectin)
Types of Administration
Injectable– Advantage – Easy to
administer– Disadvantage – Can create
problems in the meat– Disadvantage – Must be re-
dosed every 60 days
Pour-On– Advantage – Very quick to
administer– Advantage – Noninvasive
administration– Disadvantage – Must be re-
dosed every 60 days
Drench– Advantage – Very quick to
administer (not as quick as Pour-On)
– Disadvantage – Must be re-dosed every 60 days
– Disadvantage – Cow can spit out most of the product
Bolus– Advantage – Dosed only once in
the cow’s life– Disadvantage – Much longer
administration time– Disadvantage – Administration
requires training
Hypothesis
The effective drug in pour-on dewormers will affect growth and parasite infection throughout the grazing season in stocker cattle.
Control
Ivomec
Eprinex
Dectomax
Cydectin
Protocol
A
B
C
D
E
126 330
Transported by boat to Canada
-60
Transported to Feedyard,
Bruneau, ID
Transported to Swanton
Pacific Ranch
-14
Harvested at IBP,
Boise, ID
-21
Dewormed with
Dectomax
Days
0
Dewormed
70
Redewormed
Redewormed
156
Average Daily GainDay 0-105
0
0.5
1
1.5
2
2.5
Cydectin Dectomax Eprinex Ivomec Control
a a a ab
Average Body WeightDay 105
480
490
500
510
520
530
540
Cydectin Dectomax Eprinex Ivomec Control
+32.8 +31.6
+36.1
+27.6
Total Fecal Egg Count
0
50
100
150
200
250
300
350
0 28 70 105 131
Day of Study
EP
G
Cydectin
Dectomax
Eprinex
Ivomec
Control
Fecal Egg Counts Days
Treatment 0 28 70 105 126
Cydectin 0.7 4.8b 39.2b 1.6c 12.9c
Dectomax 0.8 15.6b 75.2a 2.1c 11.2c
Eprinex 2.0 1.1c 54.2ab 7.4b 21.2b
Ivomec 0.7 1.1c 86.0a 5.6b 13.8bc
Control 1.7 292.1a 57.9ab 40.2a 45.5a
ab Numbers with differing superscripts within a column differ significantly (p<.05)
RedewormedDewormed
Carcass Weights
670
675
680
685
690
695
700
Cydectin Dectomax Eprinex Ivomec Control
Yield Grade
3
3.1
3.2
3.3
3.4
3.5
Cydectin Dectomax Eprinex Ivomec Control
Backfat
0.5
0.52
0.54
0.56
0.58
0.6
Cydectin Dectomax Eprinex Ivomec Control
Ribeye Area
11
11.2
11.4
11.6
11.8
12
Cydectin Dectomax Eprinex Ivomec Control
a
ab abab
b
Marbling Score
695
700
705
710
715
720
725
730
735
Cydectin Dectomax Eprinex Ivomec Control
Yield Grade 1 & 2’s
0%
5%
10%
15%
20%
25%
30%
35%
40%
45%
Cydectin Dectomax Eprinex Ivomec Control
What does this mean?
It is important to deworm Eprinex and Cydectin equally resulted
in maximal growth Ivomec is the weakest against internal
parasites Without adequate forage, no dewormer
is fully effective
What does this mean?
Effect of dewormer during stocker phase is not significant at slaughter but effects are visible– Take advantage of cheap gain during
stocker phase rather than pay more for the gain in the feedyard
What does this mean?
Other factors must be considered when selecting a dewormer– Cost– Persistency of Protection– Ease of Administration– Rain Fastness– Flame Resistance– Customer Service
Acknowledgements
Kahua Ranch – Thank you for allowing Cal Poly to conduct the trial on their cattle
Bruneau Cattle Company – Accommodating the feedlot phase
2001 Swanton Pacific Stocker Enterprise group for participating in the data collection and organization of the trial
Brian Wetzel – Cal Poly Alumni for initiating this line of research as his senior project