RATIONAL FEEDING OF ANIMALS 347 



there is a tendency toward the production of a poor mus- 

 cular and bony framework and premature fattening. To 

 produce balanced growth in young animals, careful 

 attention should be given to the amount and nature of 

 the nutrients supplied in the food. 



472. Food Requirements of Horses. In feeding work 

 horses, the object is to provide available nutrients for the 

 production of energy because it is the energy from the 

 food which enables the horse to do his work. Experi- 

 ments have shown that for maintenance purposes, a 

 looo-pound horse requires about 17.5 pounds of hay per 

 day containing a half pound of digestible protein and 7 

 to 7.5 pounds of digestible non- nitrogenous compounds. 

 Such a ration does not provide any nutrients for work. 

 In the table at the close of the chapter are given the 

 amounts of nutrients required for average work. Any 

 increase in work should be followed by a corresponding 

 increase of food. Average work is best accomplished 

 with a ration containing 22 to 24 pounds of dry matter 

 per day of which about i . 8 pounds are digestible protein 

 and ii to 1 1.5 pounds are digestible nitrogen-free extract. 

 It is estimated that about one-third of the energy derived 

 from the food is utilized as useful energy in the perform- 

 ance of work. The best results are obtained when an 

 even draft is made upon an animal, as experiments have 

 shown that less energy is required for average work con- 

 tinuously than for severe work for a short time fol- 

 lowed by rest. 



473. Selection of Food for Morses. For light work, 5 

 to 7 pounds per day of mixed grains are usually sufficient 



