iv] CONDITIONS INFLUENCING MILK 49 



after calving. On an average it may be said to last 

 some three hundred days. An American expert who 

 has studied the question at considerable length comes 

 to the conclusion that l " on an average cows give the 

 thinnest milk just after calving ; it becomes slightly 

 richer during the next two weeks, and then it holds 

 almost uniform in quality for four or five months, 

 after which it gradually increases in richness as the 

 cow comes near to calving again, and by the ninth 

 month from last calving is only about one-seventh 

 richer than it was during the earlier months." The 

 difference in the quality of the milk due to this cause 

 is manifested almost entirely in the fat " the solids 

 not fat " remaining practically the same. E. H. Dean, 

 another American expert, has found that, dividing 

 the lactation period into three parts of ninety-one 

 days each, there was an increase in fat of only 17 

 per cent in the second period, and 46 per cent in 

 the third period, over that of the first period. 



food. The nature of the food may be mentioned 

 as a condition influencing the quality of milk. This 

 influence has been in the past both over and under- 

 rated. The old belief was that food influenced, in a 

 very direct manner, the composition of milk. The 

 modern tendency, on the other hand, is to rather 

 underestimate the effect that feeding has on milk 



1 W. W. Cook in Agricultural Science, vol. 7 (1893), pp. 253, 

 265. 



