CHAPTER X. 

 BUILDING MATERIAL. 



In order to furnish the hog with the desired material 

 for the construction of his body, it must be known where 

 and in what form these are to be obtained. 



FOOD NUTRIENTS. 



Since nutrients rather than feeds is the basis of con- 

 sideration, and is somewhat of a departure and more or 

 less unfamiliar, it is deemed advisable to discuss this mat- 

 ter in detail at this point. 



Nutrients are the ingredients or compounds of a feed 

 or of feeds such as may be used by the animal, as, for in- 

 stance, protein, carbohydrate and ether extract or fat. 

 It should be remembered that a feed must be eaten and 

 digested so as to separate it into its various constituent 

 parts, the nutrients, before they can be used. Digestible 

 nutrients are those portions of the nutrients that are ab- 

 sorbed from the alimentary tract and riot passed out in 

 the feces. 



Coefficients of Digestibility. — By coefficient of digesti- 

 bility is meant the per cent of a nutrient that is digested. 

 The total quantity eaten minus that appearing in the 

 feces divided by the total quantity, gives the coefficient 

 of digestibility or the per cent digested. According to the 

 above definition, the undigested portion of feed stuffs is 

 all found in the feces; hence in determining the coeffi- 

 cients of digestibility the feces only and not the urine 



(123) 



