292 STOCK FEEDING 



centage found of nitrogen by 6.25. The total amount of proteids 

 thus calculated is called protein. 



The fats contain carbon, hydrogen, and oxygen. Fat exists 

 in grains and in the seeds of certain plants like flax and cotton. 

 The percentage of fat in fodder is variously estimated at from 3 

 to 8 per cent of the material in the dry state. The fats are espe- 

 cially valuable as producers of energy and are capable of producing 

 two and one fourth times as much energy as an equal amount of 

 starch or sugar. The amount of fat content may be determined 

 by dissolving it with ether or other solvents. The resultant 

 quantity is known as crude fat, but after the ether has been 

 evaporated and other impurities have been removed the substance 

 remaining is known as pure fat. 



The carbohydrates consist of c irbon, hydrogen, and oxygen, 

 but the last two are always found in the same proportion as they 

 are found in water. The carbohydrates produce force and energy 

 and help to keep the body warm. If there is more of this kind of 

 food than is needed, the body stores it up in the form of 'fat, which 

 may be drawn upon at any time when needed. When the carbo- 

 hydrates are practically consumed, the body then draws upon the 

 proteids for the food necessary to keep it warm and to furnish the 

 energy required for work. The addition of these foods to those 

 containing proteid always lessens the amount of proteid required. 

 Some of the principal carbohydrates are cellulose, starch, sugars, 

 and gums. 



Cellulose is the substance of which the cell walls or the woody 

 part of the plant is mainly Composed. It is found in ripe straw, 

 in seeds, and in the stems and husks of plants. Its most familiar 

 form is the paper of commerce. The cellulose incloses the starch 

 grains, and on account of its not being very soluble it protects 

 the starch from being dissolved and washed away from plants by 

 rains. 



Starch is the common form of plant food, and it consists of solid 

 grains ranging in size from one three hundredth of an inch to 

 one four thousandth of an inch. Starch enters largely into the 

 composition of grains and of all root and tuber crops. It is readily 

 converted into grape sugar and dextrine when treated with certain 

 acids. 



