Balancing Rations Animal 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 Vegetable Proteins Come from animals or Come from plants animal by-products Common: soybean oil meal, Common: tankage, meat cottonseed meal, linseed oil scraps, meat and bonemeal, meal, peanut oil meal, corn fish meal, dried milk (whole gluten feed, brewers dried & skimmed), blood meal, grains, distillers dried grains feather meal Most contain less than 47% Most contain more than 47% crude protein crude protein Soybean oil meal is used More balanced essential most amino acids Can supply necessary Variable quality compared amino acids for swine to vegetable proteins 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. Corn 8.9 14 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. 31.8= 45.8-14 Corn 8.9 14 Soybean oil meal 45.8 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 Corn 8.9 31.8 Parts Corn 14 Soybean oil meal 45.8 5.1 Parts SBOM 36.9 36.9 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 3 parts Corn, 1 part oats 7.8 16 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.
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