10 



FEEDING VALUE OF CEREALS. 



TABLE III. Total and digestible nutrients. 

 [Pounds per hundred pounds.] 



CALORIFIC VALUE XD METABOLIZABLE ENERGY. 



When the nutrients of food are utilized within the animal body, 

 the ultimate product is either flesh or energy. The unit for measuring 

 this flesh or energy-producing power of a food is the unit of heat 

 energy or the calorie and the value so obtained is termed its calorific 

 or fuel value. 



The actual measurement of this calorific value is made in an instru- 

 ment called a calorimeter, in which an exact amount of substance 

 (e. g., one of the nutrient constituents of foods, such as fat) is burned 

 in an atmosphere of oxygen and the amount of heat so generated is 

 measured and expressed in calories. 



When 1 gram of water is raised 1 C. in temperature, the amount 

 of heat used is called a calorie. As this unit is too small for most 

 purposes, it is multiplied by 1,000; that is, the amount of heat 

 required to raise the temperature of 1,000 grams or 1 kilogram of 

 water 1 C . In English units this is equivalent to the amount of heat 

 required to raise the temperature of 1 pound of water 4 F. This 

 unit is called the large Calorie, and is written capitalized to distinguish 

 it from the small calorie. 



The total calorific value of a food is equal to the sum of the calo- 

 rific values of the different nutritive constituents. The entire food 

 is, however, not utilized by the animal, and the calorific value of 

 each nutrient must be determined not on the total amount of nutrient 

 present, but only that part w r hich is digestible. Also, in the processes 

 of digestion there are formed certain intermediate waste products 

 that still possess potential energy, and the energy of the digestible 

 portion of the food must be corrected by the amount of energy in 

 these waste products in order to determine the true amount of energy 

 in the food actually utilized by the animal. This resultant energy 



