CARBOHYDRATES 13 



plies this by 6.25 ; that is, 100 per cent divided by 6.25. 

 Feeds high in protein make up a number of the best com- 

 mercial by-product feeds, such as wheat bran, middlings, 

 linseed meal, and cottonseed meal. Farm-grown crops 

 which are high in protein are alfalfa, clover, peas, beans, 

 and peanuts. Since pratein is essential for the building of 

 living tissues, it is necessary in the feed of young growing 

 animals and milk-producing females. It is also necessary 

 in smaller amounts in the feeds of all other classes of ani- 

 mals, for from it broken-down tissue is rebuilt. 



Carbohydrates. — These are defined as substances made 

 up of carbon, hydrogen, and oxygen with the hydrogen 

 and oxygen in the same proportions as they are found in 

 the composition of water, i.e., two parts by volume of 

 hydrogen to one of oxygen. 



Included under the head of carbohydrates are starches, 

 sugars, and cellulose. Cellulose forms the cell walls of 

 plants and gives shape and stiffness to the stems, leaves, 

 and seeds. Starch is stored in the seeds of plants like corn 

 and wheat, and in roots and tubers like the potato. It 

 serves as reserve material upon which the plant draws in 

 time of need. Sugar is stored in roots as in the sugar 

 beet, and in stems as in sugar cane. 



The cellulose material is coarse and woody and makes up 

 what the chemist calls "crude fiber." It is practically 

 indigestible. 



Starch and sugar form the valuable sources of carbo- 

 hydrate feeding material. In the animal body, the carbo- 

 hydrates consist largely of glycogen or animal starch and 

 glucose, which are the forms in which this material is stored 

 to be doled out to the animal, furnishing the heat and the 

 energy necessary for doing work. When there is an excess 



