2 MANUAL OP CATTLE-FE35D1NG. 



animal takes these compounds and utilizes tlie latent en- 

 ergy wliicli tliej contain for his vital processes, the sub- 

 stances themselves uniting again with the oxygen from 

 which they were separated in the plant. In the plant the 

 spring is wound up — ^in the animal it unwinds and gives 

 out just as much force as was used in winding it up. The 

 two processes supplement each other ; the whole is a com- 

 plete circle. 



A living animal, then, is constantly decomposing and 

 oxidizing the materials of its own body. These first break 

 up in the cells of the body, independently of oxygen, in 

 accordance with the laws which regulate vital phenomena, 

 and give out part of the latent energy which they con- 

 tained. Then the oxygen of the air, carried by the blood 

 to every part of the body, seizes on the resulting substances 

 and burns them, more or less rapidly, producing a large 

 quantity of heat to replace that which the body is constantly 

 losing by radiation and otherwise, while the products of 

 this burning are finally excreted from the body. 



The body is thus continually suffering a loss of material. 

 To replace this loss, as well as to supply material for fur- 

 ther growth, is the ofliee of the food, which may, from 

 this point of view, be regarded as a vehicle for the intro- 

 duction of supplies of force into the body. 



It is the object of such a book as the present one to 

 show how much and what kind of food is needed to sup- 

 ply the losses arising under the various conditions to which 

 farm animals are subject. In order to do this intelligently, 

 we need to consider : firsts the nature and extent of the 

 processes going on in the body ; seoond^ the materials avail- 

 able as food ; and thirds the adaptation of tliese matei'ials 

 to the various purposes of feeding. The subject, then, 

 naturally divides itself into three parts : 



