36 MILK HYGIENE 



the end of the milking period. The examples are chosen 

 in order to make plain the daily variations with the 

 individual animals. 



One may find even greater variations hy examining 

 the morning and evening milk. As examples, some re- 

 sults are given from the daily examinations of milk from 

 the above mentioned cows number I and number V, the 

 figures referring alternately to the morning and the 

 evening milk on successive days : 



Cow No. 1. Cow No. V. 



Morning 3.375 3.180 



Evening 2.640 2.940 



Morning 3.240 2.710 



Evening 3.995 2.900 



Morning 2.750 



Evening 3.700 



Morning 3.800 



Evening 3.250 



Morning 4.100 2.3C0 



Evening 3.815 3.560 



Morning 4.145 4.530 



Evening 3.485 3.180 



Morning 4.085 3.220 



Evening 2.785 2.800 



Morning 3.690 



Evening 3.590 3.100 



The changes in the quantity of solids not fat (protein, 

 lactose and salts), as is apparent from the above tables, 

 are much less than those of the fat, and especially do 

 lactose and salts vary but little. 



The reasons for these daily variations in the quan- 

 titative composition of milk are not yet wholly under- 

 stood, but are to be sought in everything that in any 

 way has an unfavorable influence on the animal ; changes 

 of food (see below) or of the times of feeding and drink- 

 ing, changing to a strange place, restlessness in the sta- 

 ble, storms, oestrum, changes at milking, etc. Very often 

 no definite reason can be discovered and it appears that 



