230 THE FEEDING OF ANIMALS 



shows that the silage contains considerably less dry 

 substance than the original fresh material. Loss occurs 

 through the formation of volatile products. An examina- 

 tion of the fresh corn and of the silage shows that the 

 latter contains much less sugar than the former, some- 

 times 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 formation of acetic acid in cider and lactic 

 acid in milk, in all cases sugars being the basal com- 

 pounds. Determinations of acidity in silage by Morse 

 during several years showed it to vary from .8 to 1 per 

 cent. 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 

 proteins of the fermenting material into amino acids, 

 some of which compounds may have a more limited nutri- 

 tive function than the proteins. Investigation conducted 

 at the Pennsylvania State College showed that in some 

 cases over half the nitrogen of silage existed in the amino 

 acid or amide form* this being between two and three 

 times as much as was found in the original fodder. Proba- 

 bly the same change takes place in the field-curing of 

 fodder, but no data are available on this point. Starch 

 seems to resist the usual silo oxidations. In certain experi- 

 ments a considerable loss of nitrogen is reported. It is 

 hard to understand, though, how this can occur to any 



