CALCULATING RATIONS FOR LIVE-STOCK 319 



gestible carbohydrates and fat as of protein. The longer 

 table shows that corn has 9.8 and oat straw 33.8 times 

 as much carbohydrates and fat as protein. Evidently a 

 mixture of corn and oat straw contains too large a pro- 

 portion of carbohydrates, which means that it contains 

 too little protein. This protein can be supplied by using 

 cowpea or clover hay in place of the straw. 



In feeding animals first be sure that enough protein 

 and carbohydrates are supplied. It may be proper to 

 give a slight excess of protein if this does not increase 

 the cost. The more protein fed, the richer is the fer- 

 tilizer. 



EXAMPLE. Calculate a ration for a cow producing 22 pounds 

 of milk per day, using grass hay, cotton-seed meal, and corn. The 

 table on page 321 shows that a cow needs 2.5 pounds digestible 

 protein, 13 pounds of carbohydrates, and .5 of a pound of fat. Start 

 by guessing how much of each food might perhaps serve. Take 1 5 pounds 

 of hay, 5 pounds of corn or corn meal, and 3 pounds of cotton-seed meal. 

 By dividing the figures in the table on page 322 by 100 so as to find 

 the weight of protein, fat, etc., in every pound of grass hay, cotton-seed 

 meal, and corn respectively, the calculations in the first table can be 

 made. (See page 320.) 



The ration is thus figured to be 15 pounds grass hay, 8 pounds corn 

 meal, and 3 pounds cotton-seed meal. 



The calculated ration contains more than enough protein and fat, but 

 lacks about one pound of carbohydrates. Its excess of fat, .31 of 

 a pound (after being multiplied by 2^) makes up most of this de- 

 ficiency. The calculated ration need not contain the exact amounts 

 required in the standard rations in the short table. 



EXERCISE. In preparing this lesson pupils should rule their note- 

 books as in the next table ; copy the example ; understand how every 

 figure is obtained; and perform the suggested multiplications. To 

 work the optional problems, the notebook should be ruled in the same 

 way as in the example worked. 



