Balancing RationsAnimal Science II

Unit 8

Objectives Classify feeds as roughages and concentrates Describe the six functions of a good ration Explain the characteristics of a good ration Balance livestock rations using commonly

accepted practices

Classification of Feeds

Roughages Contain more than 18% crude fiber when dry Includes: hay, silage, pasture, fodder 2 general class: legume roughage and non-

legume roughage

Legume Roughages Can take nitrogen from the air Able to due so because they have nodules on their

roots that contain bacteria These bacteria fix the nitrogen from the air in soil

and make it available for the plant to use Do so by combining the free nitrogen with other elements

to form nitrogen compounds All the clovers, alfalfa, soybeans, trefoil, lespedeza,

peas and beans Usually higher in protein than nonlegume roughages

Nonlegume Roughages Cannot use nitrogen from the air Lower in protein Many common livestock feeds are nonlegume

Corn silage, sorghum silage, fodders, bluegrass, timothy, redtop, bromegrass, orchardgrass, fescue, costal Bermuda grass, common Bermuda grass, prairie grass (Western wheatgrass, Kentucky bluegrass, etc)

Concentrates Less than 18% crude fiber when dry Two classes

Protein supplements Energy feeds

Protein Supplements 20% or more protein Divided into 2 groups based on their source

Protein Supplements Animal proteins

Come from animals or animal by-products

Common: tankage, meat scraps, meat and bonemeal, fish meal, dried milk (whole & skimmed), blood meal, feather meal

Most contain more than 47% crude protein

More balanced essential amino acids

Variable quality compared to vegetable proteins

Vegetable Proteins Come from plants Common: soybean oil meal,

cottonseed meal, linseed oil meal, peanut oil meal, corn gluten feed, brewers dried grains, distillers dried grains

Most contain less than 47% crude protein

Soybean oil meal is used most Can supply necessary

amino acids for swine and poultry

Only protein source that can be used for ruminants

Commercial Protein Supplements Made by commercial feed

companies Mixes of animal and plant

protein feeds Usually made for 1 class of

animal Often mix of minerals,

vitamins, antibiotics Feed tag needs to be read

and feeding directions followed

Energy Feeds Feeds with less than 20% crude protein Most grains

Oats, corn, sorghum, barley, rye, wheat, ground ear corn, wheat bran, wheat middling's, dried citrus pulp, dried beet pulp, dried whey

Corn is the most widely used Followed by sorghum grain, oats, barley

Ration Characteristics

Ration Characteristics Animals need proper nutrition to efficiently produce

meat, milk, eggs, wool, work, etc A ration is the amount of feed given to an animal to

meet its needs during a twenty-four hour period A balanced ration is one that has all the nutrients the

animal needs in the right proportions and amounts Diet refers to the ration without reference to a

specific time period

Palatability Ration must taste good Mold, insect and weather damage all lower

palatability

Feed & Economics Feed accounts for approximately 75% of the

total cost of raising livestock Therefore it is necessary to develop rations

that are as economical as possible

Poisonous Plants Should not be included in the diet Sometimes grow in hay fields or pastures See Table 8-1 p.165

Balancing for Species and Age Ruminants use more roughage than

nonruminants Younger animals cannot use as much

roughage either Also need to consider the purpose for which

the animal is being fed For example fattening animals generally should

be fed less roughage than breeding animals

Micronutrients and Feed Additives Used in small quantities Care needs to be taken to thoroughly mix

these for uniform distribution Excessive amounts of micronutrients can be

harmful

Functions of the Ration

Functions of Rations Must be considered when determining

nutrient requirements Functions include

Maintenance Growth Fattening Production Work

Maintenance Primary use of nutrients is to maintain life Animals must have energy for the functioning of the

heart, breathing and other vital body processes or the basal metabolism

Energy is also needed to maintain body temperature The ration must also provide protein, vitamins and

minerals, fatty acids to replace those that are naturally lost

About ½ of the ration fed is needed for maintenance An animal on full feed will use about 1/3 of the

ration for maintenance

Growth Nutrients can only be used for growth after

maintenance requirements are met Animals mature by growing

Larger species mature slower Growth rate of large animals is faster than

that of smaller animals

Fattening Nutrients that are not used for maintenance or

growth may be used for fattening Fat is stored into the tissues of the body Fat within the muscle is called marbling

Marbling makes meat juicy and good tasting The object of fattening is to obtain the right amount

of fat in the muscle without getting too much fat Feeds that are high in carbohydrates and fats are

used for fattening

Production Cows, swine, horse, sheep, goats all produce

milk to feed their young Dairy goats and cows produce milk for

human use as well Chickens produce eggs Sheep and goats produce mohair All this production requires nutrients. The

nutrients depend on the kind of production

Reproduction Requires proper nutrition Animals may become sterile Extremely important for pregnant animals

Most of the fetus’s growth takes place during the last third of the pregnancy

Additional amounts of nutrients are needed during pregnancy

Work Horses-riding, driving Energy needed for work comes from carbohydrates,

fats, extra protein Other needs of the body are met before nutrients are

available for work Animal will use fat stored in the body for work if the

ration does not supply enough Extra salt is also needed due to animals sweating

Balancing Rations

General Principals Must meet the nutritional needs Nutrient allowance should be met as close as

possible Not more than 3% below the requirement

Dry Matter Must have a certain amount in the ration If not the animal will be hungry The digestive system will not function properly Also an upper limit that varies with the animal being

fed and its size Total dry matter in the ration of a full fed animal

should not be more than 3% above its need

Protein Measured by the total protein (TP) need of the

animal Digestible protein may also be used to

balance the ration Essential amino acids must be included when

balancing a ration for nonruminants Acceptable to allow 5-10% more protein in

the ration than the animal needs

Energy Four methods of measurement

Digestible Energy (DE) Total Digestible Energy (TDE) Metabolizable Energy (ME) Net Energy (NE)

Gross energy of feed is measured in a lab using a bomb calorimeter The feed is burned completely and the total amount of

heat released from the burning is the gross energy

Digestible Energy The gross energy of the feed minus the energy

remaining in the feces of the animal after the feed is digested

Metabolizable Energy For Ruminants

The gross energy in the feed minus the energy found in the feces, gaseous products of digestion and urine

For Non Ruminants The gross energy in the feed minus the energy

found in the feces and urine

Net Energy Metabolizable energy minus the heat increment Energy used for

Maintenance only NEm

Amount of energy used to keep the animal’s energy in equilibrium-there is no net gain or loss of energy in the animal’s body tissues

Maintenance plus production NEm+p

Production only NEp

Amount of energy need above the amount used for maintenance that is used for work, tissue growth, fat production, fetus growth, or milk, egg, or wool production and so on

Total Digestible Nutrients (TDN) Total of the digestible protein, digestible nitrogen-

free extract, digestible crude fiber and 2.25 X’s the digestible fat

Gives a measure of the total energy value of the feed when it is fed

Varies with the class of animal to which it is fed Should not be more than about 5% more than what

the animal needs

Balancing Calcium and Phosphorus Important in balancing rations Should be between a 1:1 and 2:1 ratio The ratio is more important than the total amount

being fed Total Ca and P are often more than needed when other

requirements are met Other mineral needs are usually not considered and

can be met with trace-mineralized salt

Vitamins Vitamin A is taken into account when balancing the

ration Other vitamin needs are added with out calculating

the vitamin content of the feed Vitamin A will often be more than needed but is not

harmful Vitamin deficiencies can occur in cattle and sheep

during pregnancy if low quality legume hay is fed Vitamin supplements should always be added to

pregnancy rations

Getting the Most Bang for Your Buck Some feeds are cheaper sources of nutrients than

others Energy feeds should be compared based on the price

per pound of energy (TDN, DE, ME or NE) Protein feeds should be compared in terms of price

per pound of total protein or digestible protein The least expensive source of nutrients should be

used as much as possible

Relationship Between 100% Dry Matter Basis and As-Fed Basis All feed contains some moisture and the

amount varies with the feed, form of feed, stage of growth at harvest, length of time in storage, storage conditions

The appendix in the back of the book shows the average percent dry matter in the feeds listed

100% Dry Matter Basis Data presented is calculated on the basis that

all moisture has been removed

As-Fed Basis Data is calculated on the basis of the average

amount of moisture found in the feed as it is used on the farm

Rules of Thumb for Balancing Rations

Beef See p. 172-73 in text

Swine See p. 173 in text

Sheep See p. 173 in text

Goats See p. 173 in text

Horses See p. 173-74 & Table 8-2

Poultry See p. 174 in text

Steps in Balancing a Ration

Step 1 Identify the kind, age, weight and function of

the animal(s) for which the ration is being formulated.

In our text suggested rations and feeding programs are found in the units on the specific species; these may be used for formulating rations.

Step 2 Consult the table of nutrients to determine the

nutrient need(s) of the animal(s) These requirements are called FEEDING

STANDARDS Based on average requirements May not meet the needs under specific conditions Adjustments may be needed if unusual conditions

exsists

Step 3 Choose the feeds to be used Consult the feed composition table to

determine the nutrient content of the selected feed

Nutrient contents differ with species

Step 4 Calculate the amount of each feed to be used

in the ration Sevral methods are available to do this but we

will use the Pearson Square Method

Step 5 Check the ration formulated against the needs

of the animal(s) If there is/are excessive amount(s) of a

nutrient(s) present it may be necessary to reformulate the ration

Determining Ration Costs Check the ration cost to see if it is the most

economical Calculate cost per pound or per ton Daily cost of feeding may also be calculated

if a daily consumption rate is know

Pearson Square

45

The Pearson Square Cannot balance rations by trial and error Pearson Square simplifies balancing rations Can only use two feeds

Using the Pearson Square EXAMPLE

2,000 pounds of feed is needed to feed a 100-pound growing hog. A feeding standards table shows that a 14% crude protein ration is needed. Corn and Soybean oil meal (SBOM) are selected as feeds. A feed composition table shows that corn has 8.9% and SBOM has 45.8% crude protein on an as-fed basis. How much corn and soybean oil meal need to be mixed together for 2,000 pounds of feed?

STEP 1 Draw a square with lines connecting the

opposite corners.

Write the percent of crude protein (14) in the center of the square.

14

STEP 2 Write the feeds to be used and their crude

protein percents at the left hand corners of the square.

14

Corn 8.9

Soybean oil meal 45.8

STEP 3 Subtract the smaller number from the larger,

along the diagonal lines. Write the differences at the opposite end of the diagonals.

14

Corn 8.9

Soybean oil meal 45.8

31.8= 45.8-14

5.1=14-8.9

STEP 3 The difference between the percent protein in the

soybean oil meal and the percent protein in the ration are the parts of corn needed.

The difference between the percent protein in the corn and the percent protein in the ration are the parts of soybean oil meal neeeded.

The sum of the numbers on the right equals the difference in the numbers on the left. This fact is used as a check to see if the square is set up correctly.

STEP 3

14

Corn 8.9

Soybean oil meal 45.8

31.8

5.1

36.9 36.9

Parts Corn

Parts SBOM

STEP 4 Divide the parts of each feed by the total parts

to find the percent of each feed in the ration Corn 31.8/36.9x100=86.2% Soybean oil meal 5.1/36.9x100=13.8%

STEP 5 It is known that 2,000 pounds of the mixture

is needed. To find the pounds of each feed in the mix, the percent of each feed is multiplied by the total pounds of the mix Corn 2,000 x 0.862= 1,724 pounds SBOM 2,000 x 0.138= 276 pounds

*Numbers have been rounded to full pounds.

STEP 6 Check the mix to ensure that the protein need is met.

Multiply the pounds of the feed in the it’s precent protein . Corn 1,724 x 0.089= 153 lbs of Corn SBOM 276 x 0.458= 126 lbs of SBOM

Add the pounds of protein together 153 + 126 = 279

Divide by the total weight of the mix 279/2,000 x 100= 14%

The mix is balanced for crude protein content!

Using the Pearson Square to Mix Two Grains with a Supplement (START) Can be used to find out how much of two

grains should be mixed with a supplement Proportions of grain must be known first

EXAMPLE 2,000 pound mix of corn, oats and soybean oil

meal is needed. The mix is to contain 16% Digestible Protein. A decision is made to use ¾ corn and ¼ oats in the mix. Thus, the proportion of corn to oats is 3:1. How many pounds of corn, oats and soybean oil meal are needed?

STEP 1 Need to find the weighted average percent of

protein in the corn and oats first. To do this

Multiply the proportion of corn (3) by the percent digestible protein in corn (7.1). Do the same for oats. Then add the two answers together and divide by the total parts (4). This answer is the weighted average percentage of digestible protein in the corn oats mix.

STEP 1 cont… 3 x 7.1=21.3 (Corn) 1 x 9.9= 9.9 (Oats)

31.2 31.2/4= 7.8% Digestible Protein in the corn-

oats mix

Using the Pearson Square X Used in the same method as before to mix

two feeds. On a sheet of paper, work out this problem

16

3 parts Corn, 1 part oats 7.8

Soybean oil meal 41.7

Using the Pearson Square Same method can be used for mixing two protein

supplements and 1 grain Can also be used to mix 2 grains and 2 protein

supplements Just remember that the proportions of like feed must be

decided upon before hand and the weighted average percent of protein found

Any measure of nutrients in the feed may be used Energy- TDN, NE, ME, DE Protein- CP, DP

Balancing A Swine Ration See p. 178-179 in Text

Balancing a Ration for Beef See p. 179-181 in Text

Using Algebraic Equation to Balance Ration May be used instead of Pearson Square Basic equations are

X= pounds of grain needed Y= pounds of supplement

Equation #1 X+Y= Total Pounds of Mix Needed

Equation # 2 (% Nutrient in grain) x (X) + (% Nutrient in Supplement)

x (Y)= pounds of nutrient desired in mix

EXAMPLE Same problem as the 1st Pearson Square

Example Mix of 2,000 lbs is to be balanced for protein

using two feeds.

EXAMPLE cont… Place the desired values in equation 2

REMEMBER TO EXPRESS % AS DECIMALS

0.089X+0.458Y=280 280 is found by multiplying the quantity of feed

(2,000 lbs) by the percent (14) [or the amount] of nutrient desired: 2,000x0.14)

EXAMPLE cont… Either X or Y must be canceled by the

multiplication of equation 1 by the percentage of nutrients for either X or Y, and the resulting equation 3 is subtracted from equation 2. This example uses the percentage crude protein for corn (0.089), giving equation 3 0.089X+0.089Y=178 (178 is found by

multiplying 0.089 times 2,000 lbs)

EXAMPLE cont… SUBTRACT equation 3 from equation 2

0.089X+0.458Y=280 -0.089X-0.089Y= -178

0.369Y=102 Y= 276 lbs soybean meal

X may then be found by substituting the value of Y in equation 1 and solving X+276=2,000 X=2,000-276 X= 1,724 lbs of corn

Algebraic Equations Get the same result as Pearson square May be used to balance rations using 3 or

more feeds Same initial step must be taken as when using

the Pearson Square—group similar feeds into two groups and determine the proportions of each to be used in each group After this is done the same procedure as above is

followed.