68 AGRICULTURAL EXPERIMENT STATION. [Jan. 



at least a week longer. The daily supply of protein in each 

 of the series should have been rather more regular in quan- 

 tity, thus, 1.50, 2.00, 2.50, 3.00, 3.50 pounds, etc. Some 

 rations contained more fat than others, which should have 

 been avoided, for one cannot with certainty say that this 

 increase in the fat supply of the food did not have an influ- 

 ence in increasing the fat in the milk. 



The writer would of course draw no particular conclusion 

 from this one experiment as to the effect of food, or any one 

 group of food constituents, upon the quality of the milk. 

 The results are simply presented just as they were found, 

 and show what the six cows did in this particular case. 



The experiment certainly indicates that rations so put 

 together as to contain 2.5 to 3.5 pounds of digestible protein 

 can be fed with greater profit to the farmer than rations con- 

 taining 2 pounds. 



The milk was principally affected in the first series, when 

 the change from 1.5 to 3 pounds of digestible protein was 

 made. If the change had been more gradual, it is possible 

 that but little change in the milk would have been noted. 

 It would have been interesting to note what the effect would 

 have been on the milk composition if at the end of the three 

 series the ration containing but 1.5 pounds of digestible 

 protein had again been fed. 



This experiment coincides with many previous investiga- 

 tions, only in our case the cows seemed to have been more 

 generally affected by the different rations than in case of 

 Ktihn's or Wolff's various experiments. 



