226 



Feeib and Feeding. 



m. Cow^s MUk and its By-producU. 

 IHgestibie nutrients and fertilizing constitueniM. 



* Casein and albumen. 



fMllk sugar. 



JFat. 



349. Concerning milk. — Milk is a substance designed by nature 

 for the sole purpose of nourishing young animal life. For this 

 reaaon it must always possess a peculiar interest to the student 

 (rf animal nutrition. It seems reasonable to suppose, from its 

 single purpose, that milk not only contains all the nutrients nec- 

 essary to sustain the life of young animals but that these are 

 arranged in proper proportion. 



350. Fat and serum. — The milk of the cow may be divided into 

 fat and milk serum. The percentage of fat in Hie milk of the 

 same cow may vary greatly both in the entire milk produced at 

 different periods and in different portions drawn at the same 

 milking. The first milk drawn is poor in fat, while that last 

 drawn is very rich, as is shown by the following table prepared 

 by Babcock of the Wisconsin Station: ^ 



Percentage composition of first and last milJc from the cow and of ike 

 serum — Wisconsin Station. 



Bui. 18, 



