278 



Feeding Value of Silage. 



JUNE, 



matter of the silage, while the latter indicates how much 

 of this is real albuminoid material. The difference (commonly 

 referred to as " amides ") represents nitrogenous ingredients 

 which, though not without value to the animal, do not possess 

 the full virtue of the true albuminoids. These " amides " 

 are always present to some extent in the greenstuff as it goes 

 into the silo, but the fermentation processes which take place 

 there tend to increase the proportion of " amides " at the 

 expense of the true albuminoids. Consequently, so far as the 

 feeding efficiency of its nitrogenous matter is concerned, 

 the silage is somewhat inferior to the green fodder from which 

 it is made. In the nine cases where the separate determinations 

 vveii3 made the pure albuminoids formed from 50 per cent, 

 to 81 per cent, of the crude albuminoids. 



The point is probably not of serious practical consequence, 

 however, since the silage will commonly be fed as part of a 

 mixed diet, the other ingredients of which can be made to 

 ensure an adequate supply of albuminoids. 



Carbohydrates and Fibre. — The feeding value of silage in 

 a mixed diet will be chiefly determined by its content of 

 digestible carbohydrates and fibre. The loss due to fermentation 

 in the making of silage falls more heavily upon the carbohydrates 

 than the fibre, so that the proportion of the former is somewhat 

 lower than in the original green fodder. The proportion 

 of fibre is consequently increased, but it is probably rendered 

 more digestible by the fermentative action. With the exception 

 of a Trifolium silage, the proportion of carbohydrates was 

 appreciably higher than that of fibre. 



Relative Feeding: Value of Sllagre.^ — In order to obtain an 

 estimate of the feeding values of the various silage preparations as 

 compared with each other and with roots and hay, respectively, 

 the " starch equivalent " method of assessment was used. 

 For the purposes of this method it is necessary to know not 

 only the composition, but also the digestibilit}^ of each material, 

 In the case of these silage samples, however, there was no 

 information as to their actual digestibilities, and, consequently, 

 it has been necessary to assume the same digestibility for each, 

 this being taken as the average digestibihty of oat and vetch 

 silage given in published tables of digestion co- efficients. 

 As there was no means of knowing how far this assumption 

 may have been valid, the estimates of feeding value arrived 

 at can only be regarded as rough approximations. 



The feeding Vrilues were expressed as " maintenance starch 

 equivalents," the figures representing the number of pounds 



