APPENDIX. 



205 



Table VI. Coefficients of Digestibility of American Feed 



Stuffs. — Concluded. 



EXPERIMENTS WITH BUMINANTS. 



Fuel Value of Food. 



The different classes of food compounds or nutrients in a feed, in 

 addition to their special functions of forming protein and fat, yield 

 energy in the form of heat and muscular strength. The fuel or 

 heat value of these nutrients has been measured and is expressed in 

 calories. 



A calorie is the amount of heat necessary to raise the temperature 

 of a pound of water four degrees Fahrenheit. The calories in each 

 of the three classes of nutrients are, on the average : — 



CALORIES. 



In one pound of protein 1,860 



In one pound of fats 4,220 



In one pouad of carbohydrates 1,860 



The calories in a pound of fats are equal to those in about two and 

 one-quarter pounds of protein or carbohydrates. In calculating the 

 nutritive ratio of a ration, the fats are multiplied by two and one- 

 quarter, in order to convert them into terms of carbohydrates. The 

 digestible nutrients in the standard ration for milch cows contain 

 29,600 calories. 



