326 MANAGEMENT AND BREEDING OF HORSES 



varies through wide limits, corn containing only 8%, 

 while cottonseed meal runs as high as 2>7%- 



Carbohydrates. — Most of the common foods contain 

 relatively large amounts of carbohydrate material. There 

 are two groups of carbohydrates — nitrogen-free extract 

 and crude fiber. The nitrogen-free extract is composed 

 largely of starches and sugars. It constitutes a relatively 

 high percentage of the dry matter in some of our common 

 plants, corn, wheat and potatoes running as high as 75% 

 starch. Of the various nutrients, nitrogen-free extract 

 is the most easily digested, while fiber, which constitutes 

 the tough, woody part of plants, is mostly insoluble and, 

 hence, largely indigestible. Fiber, therefore, is the least 

 valuable of the nutrients. It is noteworthy that young 

 plants contain less fiber than plants that have matured 

 and formed seed. The percentage of digestible carbo- 

 hydrates varies widely in different foods, running as low 

 as 17% in flaxseed and as high as 70% in some of the 

 cereal grains. 



Fats. — While all food contains some fat, it is present 

 in rather small quantities in all the natural foods. It 

 occurs in largest quantities in the seed, and varies widely, 

 running less than 2% in rj^e to 36% in flaxseed. Since 

 the oil content of the food is determined by extracting 

 the fat with ether, the tables of composition designate 

 the fat as ether extract. A given weight of fat will de- 

 velop from two to three times as much heat energy as an 

 equal weight of carbohydrates. 



USES OF THE FOOD 



Animals need food to maintain their existence, which is 

 dependent on matter and energy. While there are a 

 number of uses to which the energy and matter of the 

 food may be put, they can all be summed up in the fol- 

 lowing table : 



