Balancing Rations

Animal Science IIUnit 8Balancing RationsClassifying RationsRoughagesMore than 18% crude fiber when dryHard to digestInclude: hay, silage, pasture, fodder*2 classes: Legume and Non-legumeLegumes*take nitrogen from the air, it is fixed in the plan by bacteria and made available for useNonlegume*can not use nitrogen from the air, usually lower in proteinMost common livestock feedsClassifying RationsConcentratesLess than 18% crude fiber when dry2 classes-protein supplements & energy feedsProtein supplements*Contain 20% or more protein2 groups based on source- animal and vegetableCommercial supplements*Made by commercial feed companiesMixes of animal and vegetable protein feedsEach is usually made for only 1 class of animalEnergy feedsLess than 20% crude protein*Most grains*Corn is the most widely used*Ration CharacteristicsRation-the amount of feed given to an animal in a 24 hour periodBalanced ration-a ration that has all the nutrients needed in the proper proportions.Must be palatable, balanced for species, age, and functionRation FunctionsMaintenanceMaintaining the life of the animal*GrowthCan only be met after maintenance needs are met*FatteningCan only be met after maintenance and growth needs*ProductionKinds of nutrients needed depend on the type of production sought.*WorkEnergy needed comes from carbohydrates, fats and extra protein in the ration*Other needs of the body must be met first.*Balancing RationsRation must meet the needs of the animalNutrient allowance should be met as closely as possible and not more than 3% below.Ration must contain a certain amount of dry matterProtein in the RationMeasured byTotal Protein (TP)Digestible Protein (DP)Essential amino acids must be included for nonruminentsAcceptable to allow 5-10% more protein in the ration than the animal need, however too much protein will raise the cost of the ration.Four Methods of Measuring Energy Provided by the RatioDigestible Energy (DE)Total Digestible Nutrient (TDN)Metabolizable Energy (ME)Net Energy (NE)See fig 8-1

.Using a Pearson's square*EXAMPLE2,000 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 meal are selected as feeds. A feed composition table shows that corn is 8.9% and soybean oil meal has a 45.8% crude protein on as-fed basis. How much corn and how much soybean meal is needed to be mixed together for 2,000 pounds of feed.STEP 1Draw a square with lines connecting the opposite corners. Write the percent of crude protein needed in the center of the square.14STEP 2Write the feeds to be used and their crude protein percents at the left hand corners of the square.14Corn 8.9Soybean Meal 45.8STEP 3Subtract the smaller number from the larger along the diagonal lines. Write the difference at the opposite end of the diagonals.14 Corn 8.9 SBM 45.831.85.1PartsOf EachFeedneededSTEP 3To check to ensure that the square is setup correctly find the sum of the numbers on the right should equal the difference of the numbers on the left.14 Corn 8.9 SBM 45.831.85.136.936.9STEP 4Divide the parts of each feed by the total parts to find the percent of each feed in the ration.Corn 31.8/36.9 x 100= 86.2%SBM 5.1/36.9 x 100= 13.8%STEP 5It is known that 2,000 pounds of the mixture is needed. However, we need to know how much of each grain is needed to make the 2,000 pound mixture. This done by multiplying the percent of corn in the mix by the total pounds of the mix.2,000 x 0.862= 1,724 lbs of corn2,000 x 0.138= 276 lbs of soybean mealSTEP 6Check the mix to make sure the protein need is met. 1,724 lbs of Corn x 0.089= 153 lbs of corn protein276 lbs of SBM x 0.458= 126 lbs of soybean protein153 + 126= 279 pounds of protein total279/ 2,000 x 100= 14%The mix is balanced for crude protein!

Using the Pearson Square to Mix Two Grains with a Supplement*EXAMPLEAssume that a 2,000 pound mix of corn, oats and soybean meal is needed. The mix is to contain 16% digestible protein. A decision is made to use corn and oats in the mix. Thus the proportion of corn to oats is 3:1. How many pounds of corn, oats, and soybean meal are needed?Step 1The weighted average percent protein in the corn and oats is found first. Multiply the proportions of corn by the percent digestible protein in the corn. Do the same for oats. Add the two answers together and divide by the total parts. The answer is the weighted average percent of digestible protein in the corn-oats mix.Corn 3 x 7.1= 21.3Oats 1 x 9.9= 9.9 31.231.2/4= 7.8% digestible protein in the corn-oats mix.Step 2You then use the Pearson Square as in you did in example 1.16 3 parts corn plus 1 part oats 7.8SBM 41.725.7 8.233.933.9STEP 425.7/33.9 x 100= 75.8% corn-oat mix8.2/33.9 x 100= 24.1% SBMSTEP 50.758 x 2,000= 1516 lbs corn-oat mix needed1516 lbs x .75 (3/4)= 1,137 lbs of corn needed1,516 lb x .25 (1/4)= 379 lbs of oats needed.241 x 2,000= 482 lbs soybean meal needed

Step 6Check the mix.1516 x .078=118.2482x .417=200.9200.9 + 118.2= 319.1319.1/2,000= 0.159= 16%The ration is balanced for digestible protein.