256 HAKUAL OF CATILE-FEEDIJSTG. 



exact results, and may proTe of yalue to test tlie corre- 

 Bpondenee of a ration ^ ith tlio feeding standard, tliougli 

 tliey would be of but little xihe in compounding it. For 

 tills piu-pose, Stohmami's formula '^ is probably tbe bebt. 

 It is tlie following: 



7 P _ 



P 



1+V9i 



in which j>' represents the digestible protein, p the total 

 " crude protein," and s the total non-nitrogenous matters of 

 the ration, including fat. 



This formula makes the digestibility of the protein de- 

 pend on the relative amounts of nitrogenous and non- 

 nitrogenous nutrients, ignoring the influence of the amount 

 of crude fibre. For this reason, it appears to give better 

 results when applied to rations contahiing much concen- 

 trated fodder than when used for those composed exclu- 

 sively of coarse fodder. 



Finally, it must never be forgotten that these formulae 

 are entirely different from those of the mathematician. 

 They do not, like tliose, express necessary truths, nor are 

 they deduced from any well recognized natural law. They 

 are indructions, and depend for their value on the number 

 and accuracy of the observations upon w^hich they are 

 based. They may be of much value, but w^e must beware 

 of trusting them too implicitly. 



In regard to the digestibility of the protein of the 

 coarse fodders, much that is of importance and can find 

 application in practice has already been ascertained. On 

 the more important kinds of coarse fodder large numbers 

 of digestion experiments have been made, and we are able 

 to give, as the results of these, coefficients expressing the 



r r ' :• ■„ — , , , ., . .,„ , ,.,» . 1 Y in III . , I 



* Laadw. Versuchs-BtationeHj XI , 401. 



