No. 7. DEPARTMENT OF AGRICULTURE. 199 



from the practical nature of it, and tlie fact that it was conducted by 

 a man who has a national reputation as a skilled dairy feeder. 



I come now to ask your attention to a few experiments which he 

 made at this station bearing upon this same point under the imme- 

 diate supervision of Prof. Hill, whom many of you know. (This was 

 explained by means of a diagram on the black-board). 



Now, in this last experiment, if you will compare the figures for 

 available protein with the protein of the milk in the second half, you 

 will see that in the middle period of this last experiment we got 

 about dow-n to the amount of protein required for the actual protein 

 in the milk^ that is, there was no excessive protein to stimulate milk 

 production, and yet we got almost as good results so far as we can 

 judge, by comparing them in this way, that is to say, there is no 

 clear evidence in this set of three experiments that the extra amount 

 of protein received by Lot 1 or received by Lot 2 at the beginning 

 and end had any material stimulating effect. The cutting down in 

 the protein seems to have resulted simply in diminishing the amount 

 broken down while the milk production seems to have gone on, so 

 far as we can judge, at a normal rate. 



With each of these experiments, we also had a sort of an experi- 

 ment within an experiment. We took one pair of cows — one out of 

 each lot, and in addition to the general experiment, we collected the 

 excreta and made a very careful analysis so as to determine just how 

 much waste nitrogen there was; and without attempting to go into 

 the details on that technical part of it, it is sufficient to say that it 

 substantially corroborated the conclusions drawn from the more gen- 

 eral experiment. We found in this last experiment, for instance in 

 Lot 3, that there w^as just about enough protein in the ration to sup- 

 ply the maintenance demand in the bod}' and an equal amount of 

 protein in the milk. This dotted line here and black line represents 

 the result in this case upon this single animal; it is almost exactly 

 ]>arallel to the result upon the whole lot, furnishing in that respect 

 a check. To check up the matter still further, I have computed in 

 each of these experiments the results and they are tabulated and 

 found on Table 7, and are represented also on these diagrams. Here 

 is the first of it; there is a good deal of irregularity in that. Curi- 

 ously enough the lines are further apart here in the second and 

 fourth period than they are in the middle period. I think this means 

 simply that we gave a little too much feed in those two periods and 

 they were probably putting on some fat on their backs. Here are 

 the results tabulated in the same way for the second experiment; 

 you will see the black line and red line run pretty close together; no 

 very clear difference in the efficiency of the feed in the two cases. 

 In the last one there is some bowing down or sinking of the line, in- 

 dicating a lower efficiency. It is true to about the same extent in 



