198 ANNUAL REPORT. OF THE. Off. Doc. 



t)l tlic New York Agricullnral Experiment Station and some of the 

 lesulls 1 have attempted to reproduce in a simple way on some dia- 

 grams wliicli are also tabulated in tliese printed tables. The results 

 shown in Bulletin No. 132, are the results of an experimtint insti- 

 tuted primarily for another purpose. The protein supply varied con- 

 siderably as shown in Table I. The first column shows the num- 

 ber of the period and the second the number of days it covers. The 

 third column of this Table I, shows the total amount of digestible 

 matter contained in the food, so far as it was determined; the next 

 column the number of pounds of protein. The cow weighed, as you 

 see from the statement, about 870 pounds, so her body maintenance 

 requirement was about half a pound. Now, if we subtract from the 

 digestible protein food this half pound that this cow required ap 

 proximately to maintain her body tissues, the remainder w'ill show 

 how much is available for milk production or other purposes. These 

 amounts are given in the column headed, "Protein less Maintenance," 

 and you see the variations were quite considerable, ranging from 1.35 

 in the third period down to nothing, and a little less than nothing 

 in the fifth period, while the total digestible matter did not vary so 

 very greatly. It runs this high in the first period and in the second 

 and fourth it is about the same. In the third it w'as not determined. 



So far as the testimony of these two experiments would seem to 

 indicate^ it appears that below a certain limit the protein supply 

 does affect the yield of milk, in this experiment particularly, where 

 the available protein gets below 125 per cent, on what there is in the 

 milk we are apparently getting a falling off in the milk yield. These 

 three periods show a very wude range of the protein without much 

 obvious effect upon the milk production, but when we got down here 

 (referring to diagram on black-board) it is falling off evidently a good 

 deal. Somewhere in here we pass the limit below which we begin 

 to get a falling off in the milk yield due to an insufficiency of protein. 



If we were to take the testimony of these experiments alone, then 

 we should be inclined to say that if we let what I have called the 

 available protein — that is the protein minus the maintenance sup- 

 ply — if we let that fall below about 115 to 125 per cent, of what we 

 may fairly expect in the milk, we shall get a falling off in the milk 

 yield. Some other experiments which I shall present, however, may 

 incline us to modify that view a little. 



Table No. 3, is an experiment at the Minnesota Station of a more 

 practical nature than the two that I have mentioned hitherto, taken 

 from a very carefully kept record of a dairy herd of that institution, 

 divided by Prof. Hecker, who is an expert dairy feeder. He divided 

 his herd into three lots, each lot got fourteen pounds of total 

 nutrients, but with quite varying amounts of protein as you wilJ see 

 in Table No. 3. This experiment T think is particularly interesting 



