48 FARM ANIMALS 
Digestible Digestible 
Constituent Composition Coefficient Nutrient 
Protein, 3.8 «x 45 = 17 
Crude fiber, 9.7 60S) O67tC sD 
Nitrogen-free extract, 31.5 D4 61 = 192 
Fat, 160 XK ORCC 
The total digestible nutrients have been determined for each feed- 
ing stuff. Crude fiber and nitrogen-free extract, taken together, are 
often expressed as carbohydrates. Determine the digestible nutri- 
ents in corn stover, red clover hay, timothy hay, cottonseed hulls, 
corn, wheat bran, cottonseed meal, and gluten feed. 
8. Correct rations are based on digestibil- 
ity—The importance of basing all feeding 
rations on the digestible matter rather than 
on the total composition is clearly seen. 
Only a portion of the food taken into the 
stomach is assimilated. Hence, in every 
feed a part is lost and wasted. This serves 
no contribution to the nutriment of the body. 
9. Each constituent is required.—No one 
constituent can wholly take the place of an- 
other. Since protein contains nitrogen and 
sulphur in addition to carbon, hydrogen and 
aad oxygen, it is evident that neither the carbo- 
hydrates nor the fats which contain carbon, 
hydrogen and oxygen only can be substituted for protein. 
Just as the phosphorus or potassium of a fertilizer can- 
not replace nitrogen, so the carbohydrates or the fats 
cannot replace the protein of a food. While protein may 
be substituted for the carbohydrates and fats, it is to a 
limited extent, and only for a limited time. Even though 
the well-being of the animal would permit of this sub- 
stitution the added expense would be against the practice. 
10. Foods must be appetizing.—Plants are most appe- 
tizing when young and tender. They are then agreeable 
to the taste and induce a maximum consumption. At this 
