88 EXPERIMENT STATION. [Jan. 



1. By proteiu miuinmm is meant the amount of digestible 

 protein required to support the daily life of an animal of 1,000 

 pounds live weight, and amounts to about .7 of a i)ound of crude 

 protein daily; it also includes the amount contained in the milk, 

 which is about .035 of a pound for each pound of milk, or .7 

 of a pound for 20 pounds of milk. Hence the ])rotein daily 

 mininuim for a l,000-])ound cow producing 20 pounds of milk 

 would be substantially l.-t potmds of digestible protein, 



2. A large excess of digestible protein (1.5 pounds, or 100 

 per cent.) above the protein mininuim increased the flow of 

 milk some 15 per cent, in experiments extending over periods 

 of four weeks. 



3. No particular difference was noted in the milk yield in 

 case of two herds of cows receiving the same amount of total 

 digestible matter, one receiving 65 per cent, and the other 122 

 per cent, of digestible protein above the protein minimum. 

 Such a result indicates, at least, that the former excess was 

 sufficient. 



4. A 50 per cent, excess of digestible protein daily above the 

 protein minimum in an experiment by the reversal method, 

 extending over a period of nine weeks, produced some 5.9 per 

 cent, more milk than did a ration with 21 per cent, excess 

 protein. 



5. Under similar conditions an excess, above the minimum, 

 of <)5 per cent, digestible protein produced 7.4 per cent, more 

 milk than did an excess of 39 per cent. (Experiment covered 

 twenty-si X days. ) 



6. In Experiment VL, extending over a ]>eriod of eleven 

 weeks, with 12 cows by the group motlxxl, an excess of .54 

 of a pound of protein, 31.3 per cent., over the protein mininnnn. 

 produced an apparent increase of 10 per cent, in the milk yield. 



7. Tn Experiment VITL, extending over periods of twenty- 

 four to thirty weeks, with 10 cows by the group method, the 

 cows receiving the protein minimum did not shrink any more 

 than those receiving each .44 of a pound daily, or 28 per cent., 

 protein above the minimum. 



The group method of experinieiitation is best suited for 

 ConductinG: experiments M'here a i-elati\-ely large nnndier of 



