214 The Feeding of Animals 



the silo, that the silage contains considerably less dry 

 substance than the original fresh material. In some 

 way loss has occurred through the formation of volatile 

 products. An examination of the fresh corn and of the 

 silage shows, moreover, that the latter contains much 

 less sugar than the former, sometimes none at all. In 

 the place of the sugar we find a variety of acids, chiefly 

 acetic and lactic. This is a change similar to the for- 

 mation of acetic acid in cider and lactic acid in milk, 

 in all cases sugars being the basal compounds. Along 

 with the development of these acids, carbon dioxid and 

 water are formed from the carbon compounds of the 

 ensiled material. In other words, combustion takes 

 place and more or less of dry matter is actually burned 

 up, thus generating heat and causing rise of temperature 

 of the fermenting mass. The amount of dry matter 

 thus lost is determined partly by the kind of crops 

 and the care with which the silo is built and filled. 



Another important chemical change induced by fer- 

 mentation is a splitting up of a certain portion of the 

 proteids of the fermenting material into amides, com- 

 pounds which, as we have learned, have a more limited 

 nutritive function than the proteids. Investigation 

 conducted at the Pennsylvania State College showed 

 that in some cases over half the nitrogen of silage 

 existed in the amide form, this being between two and 

 three times as much as was found in the original fodder. 

 Probably the same change takes place in the field- 

 curing of fodder, but no data are available on this point. 



All observers agree so far that with normal silage 

 much the larger part of the material lost is sugar. 



