No. 7. DEPARTMENT OF AGRICULTURE. 197 



with this amount of protein in the body which is made out of food pro- 

 tein, but it is altogether probable — I am talking probabilities now — 

 it is altogether probable there is some waste in the process, and if 

 that is true, we have to increase that amount; how much we have 

 as yet no means of saying. That is a sort of speculation. 



Now, in addition to this, there is another very important ques- 

 tion, and one which has been the subject of a good deal of discus- 

 sion and one to which I expect to devote the rest of my time, and that 

 is, Does excess of protein have any tendency to stimulate the milk 

 production? Let me make that plain. We calculate that this sup- 

 posed cow of moderate capacity needs at least 6 per cent, of protein 

 and may be a little more, on account of this allowance that has to 

 be made because of changing from food proteids to body proteids. 

 She needs at least this much of protein in her daily ration. If we 

 give her more than that — two pounds instead of a pound and a quar- 

 ter — will that extra three-quarters of a pound stimulate her to pro- 

 duce any more milk? Will it make the milk-making machinery work 

 any more readily or efficiently? It has been quite generally be- 

 lieved that it does. As you know, the German feeding standard calls 

 for about two pounds of protein per day for a good dairy cow, and the 

 so-called western standard of average dairy practice with a large 

 number of good feeders calls for about two pounds and a quarter of 

 protein per day. 



You can readily see from these figures that that must be more than 

 would be required for the maintenance of an average cow and for the 

 protein actually found in her milk. Now the question is, I repeat, 

 Does such an excess tend to stimulate the milk production? Or it may 

 be put in another way^ and frequently is. We have been accustomed 

 to speak of the nutritive ratio of our various foods. Given a suitable 

 amount of digestible matter or food material by increasing the nu- 

 tritive ratio will it stimulate the production of more milk? It is 

 generally believed that that is the case. We have been taught that 

 the dairy cow requires a narrow, nutritive ration; a good deal of em- 

 phasis has been laid upon that, and rightly; the protein supply is 

 important. It is possible, however, that we have a little exaggerated 

 the necessity of it and at any rate I think we can get a little clearer 

 view of the subject if, instead of talking abou-t the nutritive ratio, we 

 attack the problem on a little different side, and speak, as I have 

 done already, of the actual amount of protein required. The cow 

 needs something besides protein and we have got to furnish enough 

 of the other required material to keep the animal machinery running; 

 but for our present purposes we can state the question I think more 

 simply by saying that so many pounds of protein are needed per head. 

 On this point, I am going to present first, the results of a few experi- 

 ments. The first one of these results is recorded in Bulletin No. 132 



