FEEDING FOR MILK PRODUCTION 275 



Water. All feeds, even those apparently dry, like corn or 

 hay, contain a portion of water varying from 10 to 15 per cent 

 with this class. Roots, such as beets and turnips, contain 

 around 90 per cent of water. The water in the feed eaten 

 serves the same purpose as ordinary water consumed by the 

 animals. 



Ash. This is the mineral part of the plant substance 

 remaining after the material is burned. It makes up the 

 greater part of the bones, and is a necessary part of all lean 

 meat. 



Protein. This important constituent is known by the 

 fact that it contains nitrogen. It serves the purpose of 

 building up tissue in the body, such as muscle, skin, etc., and 

 constitutes the curd of milk. Lean meat and the white of 

 an egg are familiar examples of nearly pure protein. All 

 feeds contain more or less protein. Among hays, clover, 

 alfalfa, cowpea, or soy bean contain the largest amount. 

 Among the common concentrates linseed meal, cotton- 

 seed meal, and wheat bran contain relatively large quan- 

 tities. A certain amount of protein is indispensable in 

 a ration, as nothing else can be substituted for it by the 

 animal. 



Crude Fiber. This is the woody part of the plant, which 

 is the least digestible. The amount of this constituent in- 

 creases with the age of the plant, and is large in feeds like 

 hays and corn stover, and small in concentrates like corn and 

 linseed meal. 



Nitrogen Kree Extract. This is a term given to a class of 

 substances much like the crude fiber in composition, but which 

 are much more easily digestible. The greater part of this 

 group* is composed of starch. 



