248 THE PRINCIPLES OP AGRICULTURE 



are the constituents of the fodder that are of 

 dh'ect use to the animal. These are often collec- 

 tively sjDoken of as nutrients, and the portion of 

 them that is digestible as digestible nutrients. 



451. Since the protein (or albuminoids) is 

 necessary to growth and reproduction, and since 

 the carbohydrates and fats are mainly used to 

 produce heat and work and reserve stores of 

 fat, the proper relations of these constituents 

 to one another in various fodders and rations 

 constitute an important part of the science and 

 art of feeding. A ration is said to be balanced 

 when these substances exist in the proper propor- 

 tion to one another for the purpose intended. 



452. It has been found convenient to express 

 the relation between the protein and other con- 

 stituents in the form of a ratio, known as the 

 nutritive ratio. The nutritive ratio is the ratio of 

 the digestible protein to the digestible carbohy- 

 drates plus two and one-fourth times (449) the 

 digestible fat, expressed in terms of unity or 

 one of the protein. 



453. The nutritive ratio is found by adding to 

 the digestible carbohydrates two and one -fourth 

 times the digestible fat, and dividing by the 

 digestible protein. It is expressed thus : Nutr. 

 Ratio 1: 5.5. It means that in some certain fod- 

 der or ration there is for each pound of digest- 

 ible protein or flesh -forming nutrients, five and 



