FEEDING DAI&Y CATTLE 105 



agreement with the standard, since the composition of the 

 feed varies to some extent and the individual requirements 

 of i he animals are also subject to some variations. 



93. The Cost of the Ration. In the foregoing, no atten- 

 tion has been given to the relative cost of the feeds used in 

 mailing up the ration. This question is one of great impor- 

 tance, and must always be taken into account. In pre- 

 paring the ration the cost should be calculated at the same 

 time, and trial made of various combinations that offer to 

 reduce the cost. 



A careful study of the figures in Table 15 will be of great 

 assistance in the selection of the most economical ration. If 

 the ration at hand is short in protein, and the purchase of 

 soi Me concentrate to supply this deficiency is contemplated, 

 a study should be made of the amount of digestible protein 

 in various feedstuff s, together with the price. A good plan 

 is to calculate the cost per pound of digestible protein to 

 ascertain in what feed it can be purchased most economically. 

 For example, if cottonseed meal costs $32 per ton, one pound 

 of digestible protein would cost 4.6 cents, if the value out- 

 side the protein be ignored. With bran at $20 per ton a 

 pound of digestible protein would cost 9.8 cents, and with 

 oats at 50 cents per bushel, or $31.25 per ton, it would be 

 worth 18.7 cents. Under these conditions it is readily seen 

 which feedstuff would be the cheapest source of protein for 

 the ration deficient in that constituent. 



If the question is that of providing the cheapest ration 

 as a whole and not merely supplying a lack of protein, it is 

 equally important to study the energy value of the several 

 feeds as carefully as is done with the protein. It is readily 

 seen, for example, that while bran has an energy value of 48.23 

 therms per 100 pounds, corn has a value of 88.84. If corn 



