LESSON EIGHT 
COMPUTATION OF RATIONS 
1. Why animals use food—An animal uses food for 
five distinct purposes: 
1. To replace waste from all parts of the body. 
2. To produce heat to keep the body warm. 
3. To produce energy so that work may be done. 
4. To provide the building materials for larger growth 
or increase in muscle, fat, flesh and bone. 
5. To have materials in reserve for the formation of 
milk, wool, etc. 
These five purposes develop after the food is absorbed, 
and originate in the digestible nutrients expressed in 
terms of protein, carbohydrates and fat. To provide 
nutrients in the quantity and proportions that they should 
be fed so as to satisfy one or more of the five ends of 
feeding makes necessary the selection and compounding 
of rations. 
2. Two kinds of rations.—Suppose a ration is wanted 
for a herd of dairy cows. What class of food shall be 
placed before the animals? It is possible to furnish a ra- 
tion consisting of roughage food raised on the farm, like 
straw, corn stover, the usual farm hays, and ear corn; 
on the other hand, a ration might be furnished consist- 
ing largely of grain food or concentrates, with a small al- 
lowance of some cheap roughage. 
In villages, and in herds near large cities, cows are fed largely 
the by-products of certain manufacturing enterprises, or on chop 
feeds and other grain materials that may be purchased often as 
cheaply as hay. The result is, these cows are not fed as they ought 
to be. The cow in the country often is fed too little protein and too 
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