190 FEEDING OF FARM STOCK. 



tion of the various nutrients in a feed which the average 

 animal digests can be closely ascertained. This matter of 

 digestibility of feeds is a very important one, since it. is 

 only what the animal digests that is going to be of benefit 

 to it. Corn cobs, for example, contain more protein and 

 nearly as much fat as corn silage, but the digestibility of 

 the protein is three times, and of the fat nearly twice, as 

 great in the silage as it is in the cobs. As a result, there- 

 fore, of the work of various investigators both in this coun- 

 try and abroad we are able to compile tables showing the 

 digestibility of the different feeding stuffs. In order then 

 to determine the amount of digestible substance, which is 

 the measure of the actual value of a feed, we simply mul- 

 tiply the amount of the nutrients contained in it by the 

 per cent, of those nutrients which is digestible. For in- 

 stance, it has been found that corn meal contains 9.2 per 

 cent, of protein, that is, in a hundred pounds of corn meal 

 there are 9.2 pounds of protein, and that the average ani- 

 mal is able to digest 68 per cent, of the protein in corn 

 meal ; therefore the amount of digestible protein in the corn 

 meal would be 9.2 x 68 per cent., or 6.25 pounds. In com- 

 puting rations and the value of feeds the digestible nutri- 

 ents instead of the total nutrients should be considered. 



NUTRITIVE RATIO. 



The term "nutritive ratio" is used so generally by the 

 student of feeding problems, farmers' institute speakers 

 and the agricultural press that a thorough imderstanding 

 ol' its meaning is necessary for all farmers who are trying 

 to feed on a rational scientific basis. By nutritive ratio is 

 meant the ratio or proportion of the digestible protein to 

 the digestible carbohydrates and fat in any given feed or 

 mixture of feeds. It is found by multiplying the amount 

 of digestible fat by 2.25 and adding the product to the 

 amount of digestible carbohydrates and dividing the sum 

 by the amount of digestible protein. The result will be 

 the number of pounds of digestible carbohydrates and fat 



