124 EIvEMENTARY TRlJATlSE ON STOCK FEEDS AND FEEDING 



Total Pounds Digestible Nutrients in ioo Lbs. of Corn Grain 



The digestible fiber is generally added to the digestible nitro- 

 gen free extract and called digestible carbohydrates. In this 

 case then the digestible carbohydrates of corn grain would be 

 65.5 -|- 1.3 = 66.8 lbs. As mentioned previously the water is 

 not considered a nutrient as it can .be supplied so much cheaper 

 by itself. The ash is also omitted because most of our feeds 

 contain enough of this substance for the needs of the animal. 



Necessity of Composition and Digestibility. — There are several 

 feeds which have practically the same chemical composition but 

 different percentages of digestibility. Therefore to ascertain the 

 real feeding value of a feed the composition and digestibility 

 should be known. 



Nutritive Ratio. — The ratio between the digestible protein 

 and the digestible carbohydrates + the digestible fats, is called 

 the nutritive ratio. This ratio is obtained in the following 

 manner. The per cent, of digestible fat is multiplied by 2.25, 

 to reduce it to terms of carbohydrates. It was previously ex- 

 plained that the fuel value of fat is 2.25 times that of carbo- 

 hydrates. This product is then added to the per cent, of digesti- 

 ble carbohydrates which gives us the total carbohydrates. This 

 sum is divided by the per cent, of digestible protein, 



(digestible fat X 2.25) + digestible carbohydrates 

 digestible protein 

 = nutritive ratio. 



To explain this more clearly let us take the digestibility of 

 corn grain, as just cited in this section. 



Digestible fat (4.3) X fuel value (2.25) = Carbohydrate 

 equivalent (9.675). 



Digestible carbohydrates (66.8) -f 9.675 = Total digestible 

 carbohydrates (76.475 ) . 



Example : 



