42 FEEDING FARM ANIMALS 



From the standpoint of composition the only dif- 

 ference between plants and animals is in the fact 

 that the former contain carbohydrates and the latter 

 do not. 



What These Compounds Do. Protein is the 

 "muscle maker" of the body; fat and carbohydrates, 

 the "heat and energy producers." The protein of 

 the plant is changed into the protein of the animal. 

 In the animal this constituent comprises the mus- 

 cular tissue, blood, hair and nerves, the internal 

 organs, skin, etc. In addition the protein is used in 

 the repair work of the body. Every beat of the 

 heart, every circuit of the blood, and every move 

 of a muscle, demands that some protein sub- 

 stance be used up. To keep the animal machine in 

 good working order these parts must be kept in 

 repair. Hence, protein at all times must replace 

 the broken parts with a new supply. If this supply 

 satisfies the waste, the weight of the animal will 

 remain unchanged. When the supply is liberal, or 

 exceeds the demands of the system, material may 

 be stored in the body as flesh or fat, and the animal 

 will gain in weight. 



Food is needed to keep animals warm. As wood 

 gives off heat when burned in the stove, so food 

 consumed in the body furnishes heat. This con- 

 sumption of fuel food is so well regulated in a 

 healthy animal that the temperature remains at the 

 same point at all times. Carbohydrates and fats 

 are mainly the sources of the heat supply. These 

 same ingredients are used for the production of fat 



