MAKUAL OF OATTLE-FEEDIKG, 247 



Crude Fibre Dig-estible. — As has been already stated 

 in a preceding chapter, a portion of the crude fibre of 

 coarse fodders is digestible. This fact is so well ascer- 

 tained, and has been so uniformly observed, that no special 

 proofs of it need be brought forward here. The amount 

 digested varies, according to the quality of the fodder and 

 other circumstances, from 25 per cent, to as high as 70 per 

 cent, of the total quantity. 



The ruminants, in particular, have the power of digest- 

 ing large amounts of crude fibre, a power due, doubtless, 

 to the great extent of their alimentary canal and the length 

 of time during which the food remains in it. They are 

 hence especially adapted to the consumption of coarse 

 fodder, such as hay and straw, and can extract from it 

 considerable quantities of nutrients, while the horse stands 

 considerably below them in this respect, and the hog 

 seems, like the carnivorous animals and man, to be able to 

 digest only young and tender fibre, such as is found in 

 roots and in young and juicy green fodder. 



The Digested Portion is Cellulose.— The "cnide 

 fibre " obtained in analysis is a mixture of cellulose and 

 " lignin," but the digested portion has been shown to con- 

 sist of cellulose only, which has exactly the composition of 

 starch (p. 39) and therefore is assumed to have the same 

 nutritive value as the latter.* 



This fact has been deduced by a comparison of the ele- 

 mentary composition of the crude fibre of the fodder and 

 of the excrement, as in tlie following example— an experi- 

 ment made at Weende in 1860-61. 



The fodder was wheat-straw, and 52 per cent, of its 

 crude fibre was digested, while 48 per cent, was found in 



* Compare page 241. 



