Exercise 2 Feed Composition and Nutrient Requirements 20 Points

Transcription

1 Exercise 2 Feed Composition and Nutrient Requirements 20 Points The objective of this laboratory exercise is to familiarize the student with the feed composition and nutrient requirement tables in the textbook. These tables list the nutrient composition of the various feedstuffs and the nutrient requirements of the various livestock species. Some of the nutrient requirements are expressed in some tables as concentration of the nutrient required in the diet (i.e. as a percentage or Kcal/kg) and in other tables as an amount of nutrient required per day. As an example, Appendix Table 12 expresses requirements of breeding beef cattle as amounts (g of protein required per day) and as concentrations (percent of protein required in the diet dry matter). It is important for the student to begin to understand trends in nutrient composition of feeds and nutrient requirements of animals. This information will become useful in subsequent exercises that involve ration formulation or the calculation of ingredient combinations which will meet the various nutrient needs of a particular livestock species. For this exercise, show calculations for Nutrient Requirements for Livestock on a separate sheet of paper, as there is little space for calculations in the table.

2 Complete the following table of forage ingredients using the Appendix Table 1. Provide the as-fed DM value and the nutrients on a DM basis. Feed ingredient DM, % Protein, % ME - Beef Cattle, Mcal/kg Calcium, % Phosphorus, % Alfalfa hay, early bloom Alfalfa hay, mature Alfalfa silage, mid bloom Timothy, fresh, late vegetative Timothy, hay, late veg Timothy, hay, mid bloom Corn silage, well eared Barley straw Wheat straw Rape, fresh Wheatgrass, Crested, hay

3 Complete the following table of concentrate ingredients using the composition tables. Provide the as-fed DM value and the nutrients on a DM basis. Use Appendix Table 1 unless otherwise indicated. Ingredient DM, % CP, % ME Beef Cattle, Mcal/kg Ca, % P, % Blood meal, Table 3 (ME Swine only) Meat &bone meal, Table 3 (ME Swine only) Barley, grain Barley, grain, Pacific Coast Corn grain #2 Cotton seeds Cottonseeds meal, solvent extracted Fish meal, medhaden, Table 3 (ME Swine only) Molasses, beet Pea seeds Oats, grain, Pacific Coast Distillers Grains (DDG) Soybean meal, solvent extr. Canola meal, solv (ingredient 68) Urea

4 From the previous two pages list the two ingredients (excluding Table 3 values) that have the highest and the two that have the lowest energy concentration (ME, Mcal/kg) content: Highest ME Lowest ME List the two feed ingredients that have the highest and the two that have the lowest crude protein concentration (%): Highest CP Lowest CP List the two feed ingredients that have the highest and the two that have the lowest calcium concentration (%): Highest Ca Lowest Ca Comparing alfalfa (legume) to timothy (grass) hay which has the greater (compare early bloom alfalfa with late vegetative timothy so that comparisons are at comparable maturities): ME CP NDF ADF Ca Of the components listed above (ME, CP, NDF, ADF, Ca), which increase with plant maturity? Which components decrease with plant maturity?

5 Nutrient Requirements for Livestock ME CP Ca Kcal/Kg Kcal/day % g/day % g/day Swine Table (old) or (new): Growing pig, kg Growing pig, kg Bred gilts and sows Ewes, 60 kg Table 18 (old) or 63 (new): First 15 wk gestation First 8 wk lactation--singles First 8 wk lactation twins Beef Cows Table 12 (old) or 46 (new): 500 kg--mid gestation 600 kg--mid gestation 600 kg nursing, avg milk 600 kg nursing, superior milk Dairy Cows Table 14 (old) or 48 (new): 600 kg--late gestation, 14 kg DM intake 600 kg--40 kg of 3.5% fat milk, 0.4 kg weight loss per day, 23 kg DM intake 1 Mcal = 1,000 Kcal; 1 Kg = 1,000 g

6 Observations and comments to make from the previous table: 1. Which pig has the greater protein requirement (% of diet) the kg or the kg pig? Comment. 2. Compare the requirements (energy, protein and Ca) of a ewe suckling a single lamb versus twin lambs. Is this logical? 3. How much do 500 and 600 kg cows weigh expressed in pounds? Compare the requirements for energy (Mcal per day) and protein (g/day) for the 500 and the 600 kg cows in mid gestation. Now compare energy and protein requirements for the two cows on a concentration of the diet basis (Mcal/kg and % protein). Explain how this can be! 4. Compare the energy (Mcal/day) and the protein (g/day) requirements of the average milking and the superior milking, 600 kg cow. Is increased weaning weight achieved from increased milk production free (have no cost to the producer)?