600 NUTRITION OF FARM ANIMALS 



TABLE 170. DIGESTIBLE NUTRIENTS REDUCED TO CARBOHYDRATE 

 EQUIVALENT 



709. T-he nutritive ratio. By the method just illustrated 

 the content of a feeding stuff in digestible matter is expressed 

 by two numbers which correspond to the two functions of the 

 nutrients already described (263) . The digestible protein shows 

 what the feeding stuff can contribute towards the structural 

 needs of the body, while the carbohydrate equivalent of the 

 digestible non-nitrogenous nutrients shows what portion of the 

 digestible nutrients can serve only as a source of fat or of energy. 

 The ratio between these two quantities gives a useful indication 

 as to whether a feeding stuff or mixture of feeding stuffs is suited 

 for forms of production like growth or milk production, which 

 require a considerable supply of protein, or whether it is better 

 adapted for those which, like work or fattening, make special 

 demands for fuel material. This so-called " nutritive ratio " 

 (better, nutrient ratio) is obtained by a simple proportion. Thus 

 in the two instances just given, it is computed as follows, the 

 second half of the proportion constituting the nutritive ratio : 



For clover hay, 5.45 : 44.58 = i : 8.2 

 For maize meal 5.85 : 77.54 = i : 13.3 



710. Significance of results. Under the stimulus of Hen- 

 neberg and Stohmann's pioneer work and under the leadership 

 of Wolff, investigation of the digestibility of feeding stuffs 

 was actively taken up in Germany and later in the United 

 States and other countries, and as the result of much labor ex- 

 pended during the last fifty years a fairly complete knowledge 

 of the amounts and proportions of the digestible nutrients sup- 

 plied by most of the ordinary feeding stuffs has been accumu- 

 lated. Extensive tables of averages have been published by 



