EXERCISE 90 



COMPUTING STANDARD RATIONS FOR DAIRY COWS 



Object. To learn the requirements of cows giving milk and the most economical sources of the 

 nutrients required. 



Materials, i. Assume that the cow is producing 24 pounds (three gallons) of milk containing 4 

 per cent butter fat daily, and that she weighs 1000 pounds; assume that corn and timothy hay are the 

 most convenient feeds to use. 



The requirement of such a cow according to the feeding standards is 29 pounds of dry matter, 2.5 

 pounds of protein, and 14. 1 pounds of carbohydrates daily. Ten pounds of corn and 15 pounds of 

 hay daily would supply approximately the amount of carbohydrates required. Ascertain whether this 

 ration furnishes the required amount of digestible protein and dry matter. Ascertain also how the 

 nutritive ratio of this ration compares with the standard. Substitute alfalfa, clover, or cowpea hay for 

 timothy, giving 10 pounds of grain and 25 pounds of hay a day, and compute the amount of each group 

 of nutrients supplied and compare them with the standards. Reduce the corn to 7 pounds daily, the 

 clover or alfalfa hay to 20 pounds, and add 2 pounds of cottonseed meal. Compute, and compare with 

 the standard in quantity of nutrients and nutritive ratio. 



2. Make a study of the rations most commonly fed in the neighborhood and compare them with the 

 standard. Suggest improvements in the amount or kind of grain used ; in the amount and kind of 

 roughage used. Ascertain to what extent the legumes are used as the principal hays and to what extent 

 silage is the principal source of non-legume roughage. 



3. Compute the nutrients contained in the rations for milk cows suggested in the text and compare 

 them with the accepted standards. Suggest other rations which might be profitably used in your 

 locality. 



Questions. Should all the cows in a herd be given the same amount of feed ? How may the proper 

 amount of grain for a cow be ascertained ? How much roughage should be fed to cows giving milk ? How 

 may one know when a cow is being underfed ? overfed ? At what season of the year is milk produced 

 at the least cost for feed, and why ? Ask an experienced dairyman of the neighborhood whether it is 

 practicable " to bring a cow back to her milk " after the milk flow has been allowed to decline. Record 

 these answers. 



References. Henry and Morrison. Feeds and Feeding Abridged, pp. 247-279. The Henry Morrison Com- 

 pany. Eckles, C. H. Dairy Cattle and Milk Production, pp. 260-287. The Macmillan Company. Waters, 

 H. J. Essentials of Agriculture, pp. 364-367. Ginn and Company. 



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