CALF FEEDING 217 
animals. The more important calf feeds are: Whole milk and 
dairy by-products, milk substitutes, hay, and various concentrates. 
Whole milk is the natural feed for calves, both as to the char- 
acter of its nutrients and the proportion in which these occur. It 
forms their sole feed for a period of a week or two to several months, 
according to the purpose in view, whether the calf is to be added 
to the breeding herd or to be vealed. 
Fic. 40.—Dairy calves in the pasture—an old-country scene. 
Only the fourth stomach (abomasum) of the new-born calf is 
fully developed; the other three compartments are small and do 
not take part in the digestion of the feed until the calf is old enough 
to eat solid feed. The lining of the fourth stomach of the young 
calf coritains a considerable amount of the ferment rennin, and 
large numbers of such calves are killed annually in Europe, espe- 
cially in Bohemia, to supply the demand for rennet stomachs used in 
the manufacture of cheese. As the calf learns to eat solid feed, 
the other compartments of the stomach gradually develop, and the 
digestive processes become similar to those of grown animals. 
The amount of whole milk required for one pound of gain will 
vary considerably, according to the age of the calves. During the 
