RELATIVE VALUES OF FEEDING STUFFS 



595 



TABLE 167. AMOUNT OF DIFFERENT FEEDS REQUIRED TO EQUAL ONE 

 FEED UNIT (Continued) 



703. Logical basis of feed unit system. The Scandinavian 

 feed unit values have a broad experimental basis. The re- 

 sults of the experiments have been reasonably consistent 

 and in general the feed unit values correspond well with the 

 relative net energy values discussed in the following chapter 

 except that they ascribe somewhat higher values to protein- 

 rich feeds. 



Nevertheless, the logical basis of the system has the same 

 defect that is inherent in all such systems. As was shown in 

 Chapter V (263), feed has two distinct functions and these func- 

 tions are incommensurable. It is as impossible to combine the 

 value of a.feed as a source of protein or other structural material 

 with its value as a source of energy, and to express the result in 

 a single number, as it is to compare the relative values of food 

 and water to a starving man. A protein-rich feed like cotton- 

 seed meal, for example, will necessarily produce a greater effect 

 when added to a ration deficient in protein than when added 

 to one containing an abundance of that ingredient; with a 

 material deficient in protein precisely the reverse would be true. 

 As a matter of fact the feed units are only claimed to be equiva- 

 lent values, " under ordinary conditions of feeding these animals, 

 when fed in mixed rations that would contain over a certain 



