CHAPTER XIV 

 THE RATIONAL FEEDING OF DAIRY STOCK 



122. Uses of Food. Food is used by the animal 

 body for three purposes : (1) for production of 

 heat and energy ; (2) for growth and to furnish 

 materials to renew the worn-out tissues of the body ; 

 and (3) for the production of animal products, as 

 milk, meat, and wool. When the animal body has 

 been supplied with food for heat, energy, and growth, 

 the excess is then available for the production of 

 meat and milk. The different nutrients or com- 

 pounds of which foods are composed serve different 

 functions in the body, and in the rational feeding of 

 farm animals it is the object to combine various food 

 stuffs so that the nutrients will be present in the 

 right amounts and proportions for the various func- 

 tions of the body. 



123. Nutrients and their Functions. The com- 

 pounds of which foods are composed are divided 

 into two main classes, the nitrogen-containing or 

 nitrogenous compounds, and those containing no 

 nitrogen or the non-nitrogenous compounds. The 

 nitrogenous compounds are spoken of collectively as 

 the crude protein of food stuffs ; the non-nitroge- 

 nous compounds are mainly starch, sugar, fat, and 



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