- - AGRICULTURE CORE CURRICULUM - - (CLF3000) Advanced Core Cluster: ANIMAL SCIENCE (CLF3150) Unit Title: NUTRITION AND FEEDS ____________________________________________________________________________ (CLF3154) Topic: DEVELOPING RATIONS Time: Year(s) 4 hours 3 / 4 ____________________________________________________________________________ Topic Objectives: Upon completion of this lesson, the student will be able to: Learning Outcome #: (B-4) - Develop a low cost (specifying actual cost) feed ration for one species of livestock for maintenance, growth, and lactation, using concentrates and roughages available from the local area. Special Materials and Equipment: Prices for various sample feeds that can be used in practice problems. References: California Farmer Magazine, the "Marketing Decisions" section of each issue. Ensminger, M.E. (1983). THE STOCKMAN'S HANDBOOK (6th ed.). Illinois: Interstate Printers and Publishers. Fridline, Clarance R. (1979). LIVESTOCK NUTRITION AND FEEDING. Ohio: Ag. Ed. Curriculum Materials Service. Maynard, Leonard, et al. (1979). ANIMAL NUTRITION (7th ed.). New York: Delmar Publishers. Resources: Vocational Education Productions, photocom for computer programs on rations. The National Academy of Sciences, National Research Council, "Nutrient Requirements of Domestic Animals", booklets and computer disks available for all livestock species, Printing and Publishing Office, 2101 Constitution Ave., Washington D.C. 20418. Evaluation: Complete practice problems. Completion of Supplementary worksheet #3. TOPIC PRESENTATION: DEVELOPING RATIONS Review: Basic Core Curriculum, Animal Science, CLF269, "Livestock Rations". A. Type of Animal 1. Before we can develop a ration, we need to determine what types of animals are to be fed. Some factors to consider are listed below: a. Species - Dairy cattle, beef cattle, sheep, horses, etc. b. Stage of growth - Mature animals have very different requirements from those of younger, growing animals. A young animal requires more protein and energy in its diet while a mature animal needs to maintain its weight only. c. Weight and Size - A small framed animal will require less feed than a larger animal of the same species. d. Gestation or Lactation - Both of these stages of production cause changes in the ration that must to be provided for optimum performance and health. B. Feed Availability 1. Different feeds are found in different areas. It is important that the stockman utilize both available and economical feeds. 2. Protein Sources - a. Usually these are expensive so you will need to determine which provide adequate amounts of protein for the animals being fed relative to cost. Some common examples are listed below: 1) alfalfa - fed to ruminants and horses, 2) cottonseed or cottonseed meal - fed to ruminants, 3) meat and bone meal - fed to swine and poultry, 4) soybean meal - fed to swine and poultry. b. When formulating rations, we tend to use crude protein (CP) rather than digestible protein (DP) because this is what is written on feed labels. Digestible protein is normally about 80 percent that of crude protein. Digestible protein can also be misleading and poorly estimated scientifically. 3. Energy Sources - a. These can be divided into two categories: high fiber and low fiber. Ruminants are more efficient at digesting high fiber feeds than non-ruminants. 1) High fiber examples: a) oat hay - fed to ruminants and horses, and b) corn silage - fed to ruminants. 2) Low fiber examples: a) corn grain - fed to all types of animals, and b) barley - also fed to all types of animals. 3) By-product feeds such as beet pulp, citrus pulp, almond hulls, barley malt, or tomato pulp (depending on digestibility) may also be fed. 4) Fats can be fed to swine, poultry, and in limited amounts to ruminants. 4. Vitamin and Mineral Needs - a. Most livestock operators are concerned with four minerals; salt (sodium and chloride), calcium, and phosphorus. These may be added in appropriate amounts to the ration. b. Often, a vitamin/mineral premix is used as it has many of the trace minerals, major minerals, and vitamins needed, and it is convenient to use. C. Determining Nutrient Needs 1. Pearson Square Method - this method is very basic and is useful when only 2 or 3 feeds make up the ration. Swine rations are good examples. (Review Basic Core for examples and worksheets.) ______________________________________________________ ACTIVITY: 1. As you "walk" through the following example with the students, draw each step on the chalk board. ______________________________________________________ a. To use this method, we must first use a reference such as THE STOCKMAN'S HANDBOOK or the series on "NUTRIENT REQUIREMENTS OF DOMESTIC ANIMALS" to estimate nutrient requirements for a specific animal. Let's use a pig that weighs between 44 - 77 pounds, and is gaining weight at 3 pounds/day. b. Determine, using references, the percent protein required in the diet. According to the reference, THE STOCKMAN'S HANDBOOK,this pig requires a 16 percent crude protein ration. c. Next, select the feeds you have available in your area. For this example, we'll use a pre-mixed protein supplement containing 36 percent protein and corn which contains 10 percent protein. d. To determine how to mix these feeds to provide a ration containing 16 percent protein, we will need to draw a square and place the number 16 in the center. e. At the upper left hand corner of the square, write "Protein Supplement" and its protein content (36). f. At the lower left hand corner of the square, write "Corn" and its protein content (10). g. Now, subtract diagonally across the square and write the differences on the right hand sides for each. h. The number at the upper right hand gives the parts of protein supplement by weight and the number at the lower right hand gives the parts of corn by weight. i. The answers for this example are 6 parts protein supplement and 20 parts corn for a total of 26 parts. j. Using the above information, you can now determine the percent of each feed in the ration. For example, 6 divided by 26 equals 25 percent protein supplement and 20 divided by 26 equals 75 percent corn. ___________________________________________________________ ACTIVITY: 1. Practice problems using other feeds and other types of animals. ___________________________________________________________ 2. Disadvantages of the Pearson Square Method a. As you may have already discovered, this method works best using only 2 types of feeds. (If 3 feeds are used, we must average their protein content.) b. It only balances the ration for protein or any other single nutrient at a time. 3. Trial and Error Method a. This method allows you to determine nutrient needs using a variety of feeds and so it is more applicable to ruminant animals. It also allows you to balance the ration for minerals and vitamins as well as protein and energy. 1) We must first use a reference such as the STOCKMAN'S HANDBOOK (or other sources of feed composition tables) to estimate nutrient requirements for a specific animal. Let's use a 661 pound Holstein heifer. 2) Using the reference, we find her requirements for growth to be as follows: Crude protein (CP) 1.70 pounds per day and TDN (energy) 10.05 pounds per day. 3) Let's say, her calcium, phosphorus, and trace mineral needs are taken care of by using a mineral pre-mix added to the grain portion of the ration. Salt is fed free choice. 4) Choose the feeds available in your area and determine their nutrient content using your reference. We will use: =============================================================== feed TDN percent CP percent _______________________________________________________________ Alfalfa Hay 50.3 15.5 Corn 80.3 9.5 Corn Silage 16.3 2.0 Cottonseed 88.7 23.1 Oats 67.2 11.7 =============================================================== 5) Next, we must estimate the amount of roughage this heifer will be consuming. We'll start with 7 pounds of alfalfa and 15 pounds of silage. This is determined by assuming the heifer will consume 3% of her body weight/day (also found in tables). 6) Now, to determine the amount of TDN in pounds that is being supplied by the alfalfa, we multiply the amount being fed (7 pounds of alfalfa) by its percent TDN (50.3 percent) and by doing this we find that this heifer is receiving 3.53 pounds of TDN each day from the alfalfa she is being fed. 7) We do the same calculation to determine the amount of TDN in the corn silage, so if 15 pounds of silage is multiplied by the percent TDN found in silage (16.3 percent), then we determine that she is getting 2.45 pounds of TDN each day from the silage. 8) Now, we need to determine the amount of CP (crude protein) she receives from the corn silage and alfalfa. Using the same method, we find that she receives 1.09 pounds of CP from the alfalfa and .30 pounds of CP from the silage. 9) By adding the two TDN's together we see that her current diet (alfalfa and silage ) supplies 5.97 pounds of TDN per day and she requires 10.05 pounds of TDN. By adding the two CP's together, we see that the diet supplies 1.39 pounds of CP and she requires 1.70 pounds. 10) We still need to supply 4.08 pounds of TDN (10.07 pounds required minus 5.97 supplied) and .31 pounds of CP (1.70 pounds required minus 1.39 supplied) by using our other feeds. 11) Let's add 1 pound of cottonseed and 5 pounds of corn and see what happens. 12) The cottonseed supplies .89 pounds TDN and .23 pounds of CP. The corn supplies 4.02 pounds of TDN and .82 pounds of CP. If we use this ration of: ================================================================= feed TDN (pounds) CP (pounds) _________________________________________________________________ 7 lbs alfalfa 3.52 1.09 15 lbs silage 2.45 .30 5 lbs corn 4.02 .82 1 lb cottonseed .89 .23 _________________________________________________________________ Pounds supplied 10.09 lbs 2.51 lbs ================================================================= We meet and exceed the requirements listed in our reference for energy and protein. __________________________________________________________ ACTIVITY: 1. Use the references listed and do practice problems for a smaller heifer, a bred heifer, a dry cow, and an average producing lactating cow. __________________________________________________________ D. Least Cost Rations 1. Determining the cost of a ration is nearly as important as balancing it for nutrients. Some factors to remember when formulating a ration are: a. Protein supplements are expensive and YOU NEVER USE THESE TO SUPPLY ENERGY. b. Utilize by-product feeds in your area if they are inexpensive sources of energy. Some examples: 1) almond hulls, 2) barley malt, or 3) citrus or tomato pulp. c. Figure cost per pound - hay and other feeds are often purchased by the ton. (There are 2000 pounds in a ton or 100 pounds in a cwt -- known as "hundred-weight".) 2. Calculating costs - below is the cost of the ration we balanced earlier: =================================================================== Feed Amt. Cost\unit Cost of the ration ___________________________________________________________________ Silage 15 lbs $12.00\ton $00.09 Alfalfa 7 lbs $108.00\ton $00.38 Corn 5 lbs $6.76\cwt. $00.34 Cottonseeds 1 lb $170.00\ton $00.09 ___________________________________________________________________ Total cost/per head/per day $00.90\hd\day =================================================================== 3. How could we make this ration more economical and still meet nutrient requirements? Use your own judgement. We could increase the amount of corn and eliminate the cottonseed. Let's try. 4. Here is what happens when we change the ration: =================================================================== Pounds Feed TDN CP ___________________________________________________________________ 7 Alfalfa 3.52 1.09 15 Silage 2.45 .30 6 Corn 4.82 .57 ___________________________________________________________________ Total nutrients supplied 10.79 1.96 =================================================================== If you check the nutrient requirements mentioned earlier you will find that this ration does meet all requirements. In addition, this ration is $00.03 less expensive than the other ration. This savings would amount to $10.95 per head per year. If you owned 100 head of heifers, this would save you $1095.00/year! 5. Computer programs for ration formulation and least cost rations are available and are used by many feedlots and dairies. __________________________________________________________ ACTIVITY: 1. Determine the cost of sample rations fed to project animals. 2. See Supplemental Worksheet #3 for practice problems. __________________________________________________________ SUPPLEMENTAL WORKSHEET #3 RATION FORMULATION NAME_________________________________ DATE_________________________________ PERIOD_______________________________ 1. Use a reference to find the nutrient requirements for the following animals: ============================================================================ Animal Pounds of CP Pounds of TDN ============================================================================ | | 200 lb calf | | __________________________|______________________________|__________________ | | 400 lb heifer | | __________________________|______________________________|__________________ a) 0.5-1.5 lbs/day | | __________________________|______________________________|__________________ b) 1.5-2.5 lbs/day | | __________________________|______________________________|__________________ 700 lb heifer | | __________________________|______________________________|__________________ 900 lb bred heifer | | __________________________|______________________________|__________________ 1200 lb dry cow | | __________________________|______________________________|__________________ 1200 lb lactating cow | | __________________________|______________________________|__________________ a) 100 lbs/day milk | | __________________________|______________________________|__________________ b) 75 lbs/day milk | | __________________________|______________________________|__________________ c) 40 lbs/day milk | | __________________________|______________________________|__________________ 2. Slower growth gain is cheaper by the day but much more expensive in the long run, why? 3. Discuss how the dietary protein requirements change in the above example: 4. Use the Pearson Square method to calculate the following: a) List the protein requirement for a 200 lb. market hog:______________ b) List two types of feed to be used in the ration: #1______________________________ and #2______________________________. c) List the percent protein supplied by: #1______________________________ and #2______________________________. 5. Calculate the following using the Pearson Square: __________ lbs. of protein supplement __________ lbs. of other feed __________ Total __________ Percent protein supplement in ration __________ Percent other feed 6. Now, use 2 different feeds and do the same calculations, (Show your work on the back of this page). 7. Give the cost per pound of each of the feeds used in the above problems. Feed #1 cost________________________ Feed #2 cost________________________ Feed #3 cost________________________ Feed #4 cost________________________ 8. Calculate the total cost of each ration used above. Which is cheapest? 9. Use the "Trial and Error" method to balance a ration for a 1400 lb cow during the last 2 months of gestation. Complete the helpful hints below: ===================================================================== Feed Cost per lb. CP percent TDN percent ___________________________________________________________________ | | | | Alfalfa | | | | _____________|_________________|_________________|_________________| Corn Silage | | | | a. | | | | | | | | _____________|_________________|_________________|_________________| b. | | | | | | | | _____________|_________________|_________________|_________________| c. | | | | | | | | ===================================================================== How many pounds of TDN does this cow need? ___________________ How many pounds of CP does this cow need?_____________________ This cow in currently getting 15 pounds of alfalfa and 40 pounds of corn silage. How many pounds of CP and TDN are being supplied? Corn Silage _________________lbs. TDN _________________lbs. CP Alfalfa _________________lbs. TDN _________________lbs. CP Total left to be supplied by other feeds: ______________________________ Now calculate how much of each feed you will use. Show your work on the back of this paper. What is the cost of this ration per head per day? 5/4/90sg #%&C