THE FEEDING OF LIVE STOCK. 161 
CHAPTER XIII. 
THE FEEDING OF LIVE STOCK. 
No one kind of food, unless we except milk, 
meets all the requirements of the domesticated 
animal. The composition of all others is one- 
sided, and it is essential that two or more foods 
be fed so as to give a ration that will be fairly 
balanced, and not one-sided. Some foods are 
more nearly perfect for certain animals than 
others, but combinations usually bring about 
the best results in feeding. 
Constituents of foods.—The chemist who an- 
alyzes a food finds it composed of several groups 
of substances quite different in character. For 
the feeder’s purpose three of these only need 
be considered. First is the protec, consisting 
of a class of bodies best represented in the com- 
position of the white of an egg or in perfectly 
lean meat. The muscles of the body consist 
mainly of protein. Another group is known as 
carbohydrates, or heat-formers. These consist 
mostly of starch, sugar, and woody fibre or cel- 
lulose. The third group is the fat of the plant, 
as for example the oil extracted from the cot- 
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