RELATIVE VALUES OF FEEDING STUFFS 



599 



708. The digestible nutrients. The methods of digestion 

 experiments as used by Henneberg and Stohmann and modified 

 by later experimenters were outlined in Chapter III (157-161). 

 A vast number of determinations of digestibility have been 

 made, upon a great variety of materials, and the results have 

 served as the basis for computing the relative values of feeding 

 stuffs. The method of comparison may be illustrated by 

 means of the digestion experiment on clover hay and maize 

 meal used in Chapter III to illustrate the method. (Table 168.) 



Simplified statement. Since the digestible crude fiber and 

 digestible nitrogen-free extract have been shown (168, 169) to 

 have the elementary composition of starch, they have been 

 commonly added together and called carbohydrates. Con- 

 sidering the digestible ether extract to be substantially fat, 

 and omitting the ash on the assumption that an average 

 ration contains a sufficient supply, the amounts of the three 

 principal groups of digestible nutrients may be stated more 

 concisely as follows : 



TABLE 169. SIMPLIFIED STATEMENT OF DIGESTIBLE NUTRIENTS 



This statement may be still further simplified. A pound 

 of fat produces when burned about 2.25 times as much heat as 

 the same weight of carbohydrates. The non-proteins have ap- 

 proximately the same heat value as the carbohydrates, while 

 it is still questioned whether they help to build up protein tis- 

 sue. By multiplying the digestible fat by the factor 2.25 and 

 adding the digestible carbohydrates and non-protein we obtain 

 the carbohydrate equivalent for the digestible matter other 

 than protein and the digestible nutrients may be expressed in 

 the following still more concise form : 



