CHAPTER VIII 
CALCULATION OF RATIONS 
QUESTIONS relating to rations for the various classes of farm ani- 
mals will be considered in detail later on, in the discussion of feeding 
problems connected with the respective animals. We shall here give 
the general method by which rations are calculated from the tables of 
composition and digestibility of feeding stuffs. 
The Wolff-Lehmann Standard.—We shall suppose that a 
milch cow yielding about 20 pounds of milk daily is to be fed a 
ration composed of the following feeds: Hay from mixed grasses, 
corn meal, wheat bran, and oil meal. Experience has taught us that 
a cow will eat, on the average, about 20 pounds of hay daily, with a 
fair allowance of concentrates. It is a good plan to feed concen- 
trates in proportion to the amount of milk or butter fat produced by 
the cows. We will assume that the cow will receive as a trial ration, 
in addition to the amount of hay given, three pounds of corn meal 
and four pounds of wheat bran. From Table I in the Appendix we 
learn the composition of hay, corn meal, and bran. 
Ingredients for a Trial Ration 
. : Digestibl 
Diy, | Digeno | ,Migertibe., 
pounds pounds aN 
100 pounds of hay contain.........: 84.7 4.2 44.9 
100 pounds of corn meal contain.... 88.7 8.0 75.9 
100 pounds of wheat bran contain... 88.1 11.9 47.6 
Twenty pounds of hay, therefore, contain: 
-847 X 20= 16.94 pounds dry matter; 
042 X 20=—= —.84 pound digestible protein; and 
449 X 20= 8.98 pounds digestible carbohydrates and fat. 
In the same way three pounds of corn meal will contain: 
.887 X 3= 2.66 -_pounds dry matter; 
08 X3—= .24 pound digestible protein; 
.759 X 3==2.28 pounds digestible carbohydrates and fat; and- 
Four pounds of wheat bran will be found to contain: 
3.52 pounds dry matter; 
.48 pound digestible protein, and 
1.90 pounds digestible carbohydrates and fat. 
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