XIV. 



FOODS AND FEEDING. 



295 



equivalent is close, in green fodders grasses and leguminous plants 

 the former is from 80 to 90 per cent of the latter, in silage and root 

 crops it is usually from 70 to 80 per cent, in hays from 60 to 70 per 

 cent, while in straws it ranges from 30 to 50 per cent. In certain 

 woody "foods," e.g., husks, sawdust, the energy expended in their 

 mastication and digestion is greater than that yielded by their food 

 constituents ; such material may therefore be said to possess a negative 

 value as foodstuffs. 



This table can obviously lay claim to no great accuracy ; the great 

 variations in composition of different samples of foodstuffs of the 

 same type, as well as the often great differences in digestibility of its 

 constituents render it impossible to obtain data which shall always be 

 reliable. Moreover, as has been shown, digestibility varies very much 

 with different animals. 



Importance of " Albuminoid Ratio." It has been usual in 

 the past to attach great importance, in discussing the framing of 

 rations of fattening animals, to the ratio of albuminoids to non-albu- 

 minoids in the digestible portion of the food. A considerable amount 



