66 MANUAL OF MILK PRODUCTS 



lb. milk a day and during the thirty days the decline was slight. 

 At the end of thirty days she was producing 19-J lb. a day. 

 During this time the live weight decreased 115 lb. The per- 

 centage of fat in the milk was taken by extraction after the usual 

 chemical method on each second day. The results are shown 

 in the table. It will be noted that the percentage of fat is 

 unusually high down to the twenty-fourth day. As soon as the 

 feed was raised to near normal amount the percentage of fat 

 immediately dropped from between 5.5 and 6.0 to close to 4.5. 

 It will be noted further that the percentage of fat remained low 

 from the thirty-fourth day to the fifty-eighth. During the 

 remainder of this lactation period this animal was kept on a 

 normal ration and the percentage fat for the third month, that 

 is, the next following the figures given, was 4.0 per cent. The 

 fourth month was 4.10; fifth month 4.5; sixth month 5.2; 

 seventh month 5.2 ; eighth month 5.6 ; ninth month 5.5 per 

 cent. The average for the entire year was 4.8 per cent. It will 

 be seen from this that the percentage of fat during this first 

 thirty days' period was entirely abnormal for this animal. 

 Records are available for the same cow for three complete 

 lactation periods in addition, during which she varied from 4.6 

 to 5.3 as an average." 



From the results of his work on this subject Eckles draws the 

 following conclusions : 



" The percentage of fat in milk can be influenced to a marked 

 extent for the first twenty to thirty days by the fatness of the 

 animal at parturition. This influence appears to extend in some 

 cases in a less degree for at least three months. 



" Under-feeding of the animal after parturition seems to be a 

 necessary condition to bring about this abnormal percentage of 

 fat in the milk." 

 Effect of period of heat. 



For the purpose of acquiring definite information on this 

 subject, Doane analyzed the milk of individual cows in normal 



