MANUAL OF CATTLE- FEIDIK^. 51 



Nitrogen-free Extract, — All that remains of tlie dry 

 matter of tlie fodder, after deducting tlie erode protein, 

 crude fibre, crude fat, and asli, is designated aBiiitiogen- 

 free extract (K. f r. E\tr.) ; that ib, tlie <|uaiitity of tlie lat- 

 ter is determined by difference. 



Ill all grains and roots tliis is of a tolerably simple na- 

 ture, and consists chiefly of starch or sugar and bodies of 

 the pectin group, and sometimes of vegetable nnieilage, 

 which has a composition analogous to that of starch and 

 exerts, probably, an equal nutriti\ e effect. 



But in green and coarse fodders we have, in addition, 

 varying quantities of gum-like substances and of iigniii, 

 which latter partly dissolves when the fodder is treated 

 with acids and alkalies, but, at the same time, appears not 

 to be resorbed in the alimentary canal, and therefore not 

 to contribute to the nourishment of the animal. 



Ob the other hand, we shall see further on that all of 

 the nitrogen-free extract which is really digested has the 

 percentage composition of starch, and that, theiefore, the 

 non-nitrogenous nutrients of fodders, with the exception 

 of fat, may be considered in general as carbhydrates. 



The small quantities of organic acids and other bodies 

 piesent are of no direct importance as nutrients, though 

 they often have an important indirect influence, either bj 

 imparting to the fodder an agreeable taste or smell, or the 

 reverse, by some specific physiological action^ or by impart- 

 ing iihdesirable properties to the products of the animal 

 — ^. ^.5 the well-known effect of cabbage, rape cake, or 

 onions on milk. 



f3"utritive Ratio. — ^Along with the composition of a 

 fodder we usually find given its nutHtim ratio, by which 

 we understand the ratio of the digestible protein to titie 

 digestible non-nitrogenous nutrients. 



