196 ANNUAL. KEPORT. OF THE. Oft. Doc. 



neighborhood of six-tenths of a pound for a thousand-pound animal. 

 From somewhat extensive experiments that have been made both 

 iiere and elsewhere upon this point, we have, as a net result, this 

 amount of six-tenths of a pound for the thousand-pound animal, and 

 I think we may say safely that this amount is ample for such an ani- 

 mal. It is possible that somewhat less would answer, but we are 

 reasonably certain that that is enough. We may say then that the 

 ration of our dairy cow must contain six-tenths of a pound of protein. 

 Now, in addition, there is the casein and albumin in the milk which 

 can be made out of the protein of the food. Now we can figure up 

 that, approximately, without any difficulty. It depends of course 

 upon how much milk our cow gives. Let us take a moderate yield 

 of twenty pounds of milk a day, not a very heavy yield; the amount 

 of protein in that milk, will vary somewhat, of course, according to 

 the breed and individuality of the cow and the quality of milk that 

 she gives. In a general way, we can say, that about one quarter of 

 the dry matter in milk will be protein; that milk contains, we will 

 say, thirteen and a half per cent, of solids, that would be equivalent 

 to two and seven-tenths pounds of protein per day, one quarter of 

 that being .675 pounds of protein. Under these assumed conditions, 

 then, it is evident that we must have in the ration of that cow a lit- 

 tle less than seven-tenths of a pound of protein simply to make the 

 protein in the milk because the animal body cannot make protein out 

 of anything else. We also must have 1.275 as the least amount of 

 protein that that cow can get along with. It requires .6 of a pound 

 to maintain her body or tissues. Since there is this amount of .675 in 

 the milk, we must supply that much in the food if we don't want to 

 draw upon the body. This would represent the minimum. If we 

 suppose that cow to give thirty pounds of milk with, say 15 per cent, 

 of solids, there would be four and a half pounds of solids a day and 

 a quarter of that would be .125 pounds of protein approximately in 

 the milk; and add six-tenths to that, you will have .173, in round num- 

 bers. So the protein supply would depend on how^ much milk she 

 is capable of producing. You strike there a very important idea, 

 namely, the modification of the ration in accordance with the capa- 

 city of the cow. There are some other things to be taken into con- 

 sideration. This protein — take this example — is chiefly in the form 

 of casein with a little albumin. Now we do not give our cow casein 

 or albumin in her food; we give her proteids which are similar, but 

 not casein and albumin. 



Now as to the matter of waste, it is somewhat as if you were to 

 take down a shed and re-build it in a different shape in a new place. 

 You could not do that without some waste material. There would 

 be some pieces that would not fit in the new place and there would 

 be some waste material. It is probable something the same is true 



