558 



ANNUAL REPORT OF THE 



Off. Doc. 



(c.) Age. — So far as published dafa throw light upon the question 

 of the inlluenee of age upon Ihe amount of fat in milk, the more 

 conjuiou tendency appears to be for milk to become less rich in fat 

 with each succeeding period of lactation, especially after the second, 

 though individual exceptions to this tendency are not infre(]uen(. 

 We need more extended data bearing upon this point before we < .ni 

 speak with any degree of positiveness. 



(d.) Advance of Lactation Period. — In general, it is found that 

 the per cent, of fat in milk increases as the stage of lactation ad- 

 vances. The following figures represeut the averages obtained from 

 ao aggregate of nearly fifty lactation periods of diffeienl cows, cov- 

 ering a period of ten months: 



Number of Month of Lactation. 





First, .. 

 Second, 

 Third, . 

 Fourth, 

 Fifth, .. 

 Sixth. . 

 Seventh, 

 Eighth, 

 Ninth, . 

 Tenth, . 



4.54 

 4.33 

 4.28 

 4.39 

 4.38 

 4.63 

 4.56 

 4.6(! 

 4 7P 

 5. Of' 



(e.) Variation of Time Between Milkings. — As a rule, the longer 

 the time between two successive milkings, the smaller is the per 

 cent, of fat in the milk, and the shorter the time between milkings, 

 the greater the per cent, of fat. When the time between milkings 

 is uniformly equal, the variation of fat in milk is small, provided the 

 general conditions surrounding the cow are the same. However, 

 as there is not commonly such entirel}' uniform condition of sur- 

 roundings during the day and night, there is probably a common 

 tendency in the direction of a little more fat in the morning's milk. 



(f.) Relation of Yield of Milk to Fat. — Large yields of milk are 

 usually, though not necessarily, accompanied by lower percentages 

 of milkfat, while smaller yields are more commonly associated with 

 larger percentages of fat. 



(g.) Influence of Food Upon Amount of Fat in Milk. — This ques- 

 tion has been the subject of investigation for 3'ears, but we are 

 not yet able to say that we can "feed fat into milk," under ordinary, 

 normal, practicable conditions. It has been noticed by several in- 

 vestigators that a very marked change in the general character 



