MAKTJAIi OF OATTLE-FEEDIlSra. 285 



tion of bye-fodder, will serve to give an idea of the extent 

 of tlie depression. The numbers denote the decrease in 

 the digestibility of the protein, nitrogen-free extract, and 

 total organic matter, nnder the influence respectively ^f 

 roots and potatoes. The depression is calculated in per- 

 centages of the amounts of the several nutrients digested 

 when the bye-fodder was withheld. 



The decrease in the digestibility of the non-nitrogenous 

 ingredients caused by any amount of roots or potatoes likely 

 to be fed in practice is so small that we may neglect it, and 

 consider only the effect on the protein. 



From the above numbers, Wolff concludes tfiat we can 

 assume that, when the dry matter of the bye-fodder of 

 ruminants amounts to ^^ J, -J-, and finally equals that of 

 the coarse fodder, the digestibility of the crude protein of 

 the latter is decreased by about 7, 14, 28, and 40 per cent, 

 if the bye-fodder consists of potatoes, and by about half 

 5is much if it consists of roots. 



It is plain, however, that these numbers can be but ap- 

 proximations, since, in general, the decrease of the digesti- 

 bility varies with the nutritive ratio of the whole ration. 

 It seems probable that, in practice, the most satisfactory 

 method would be to use these iigures as a basis for com- 

 pounding a ration, and then to compute the digestibility 

 of the total crude protein by means of Stohmann's for- 

 mula (p. 256). In cases of doubt, it is well to eir in giv- 

 ing slightly too much rather than too little protein, not only 

 for the sake of ensuring the digestion of the non-nitroge- 

 nous nutrients but to ensure also a sufficient supply of the 

 important albuminoids to the animal. 



For similar reasons it is well, when feeding large quan- 

 tities of roots along with hay or straw, to add to the ra- 

 tion a small amount of some highly nitrogenous bye-fod- 



