250 THE PRINCIPLES OF AGRICULTURE 



source of heat, instead of the cheaper starch or 

 sugar. This may occur in any ration when the 

 proportion of protein is in excess ; but there is 

 generally a too small proportion of protein. 



457. By far the larger number of natural 

 fodders are deficient in protein, and a chief task 

 of the feeder is to furnish, from by-products or 

 otherwise, a sufficient amount of albuminoids in 

 the cheapest form. Usually more protein can 

 be used to advantage by the animal than is 

 furnished to it. 



46. Quantity of food required 



458. The quantity of food that an animal can 

 profitably or economically use is dependent upon a, 

 variety of circumstances and conditions. In the 

 first place, a certain amount must go to the sup- 

 port of the body and the vital functions. This is 

 known as the food of maintenance (432) ; and 

 a ration calculated to keep an animal alive and 

 in good health without gain or loss of body 

 weight is called a maintenance ration. 



459. The amount of food required for sup- 

 port depends upon the size and somewhat upon 

 the individuality of the animal. Small animals 

 require more food in proportion to their weight 

 than large ones. Average animals of the same 

 class, however, are usually considered to require 

 food in proportion to their body weight. In 



