CHAPTER II 

 THE FEEDING OF ANIMALS — GENERAL DISCUSSION 



The economic feeding of farm animals involves a knowledge 

 of the principles underlying the practice. The better knowl- 

 edge one has of the food, its source, use, composition, and di- 

 gestibility, the more familiar he is with the function of the 

 various food materials, and the balancing of rations, the more 

 intelligently can he choose the foods that constitute the ration. 



FOOD 



Food may be defined as any material that an animal can 

 take into its digestive organs and from which it can absorb 

 matter for the nourishment of its own body. Plants and their 

 products and by-products constitute the food of farm animals, 

 although some farm animals are in part carnivorous, feeding 

 on other animals or parts of animals. Matter is transferred 

 directly from the food to the tissue with or without chemical 

 or physical change. Materials is not, however, the only thing 

 the animal gets from the food. The plant during growth absorbs 

 heat from the sun, which is held in latent form in the plant 

 compounds. When these compounds are taken into the ani- 

 mal body and broken apart by digestion, some of this stored 

 heat may be transferred to energy. The animal therefore gets 

 from the food both matter and energy. 



Use of food. — The matter and energy the animal collects 

 from the food are put to three distinct uses : first, to support 

 life; second, to reproduce life; and third, stored up in some 



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