COMPOSITION OF PLANTS AND FEEDS 385 



Silage. Silage is a feeding-stuff preserved in a moist condi- 

 tion. It is made by placing the finely chopped material in an air 

 tight receptable. More or less fermentation takes place, 1 which 

 destroys sugar, produces acids, and causes the loss of ten or twelve, 

 per cent, substance. The acidity of the silage depends upon the 

 conditions of preparation. If a silo is filled rapidly, the mass 

 weighted down and the air excluded as much as possible, a slow 

 fermentation takes place caused by bacteria, which results in a 

 very acid product, termed sour silage. It may contain 0.6 to 1.6 

 per cent. acid. If the material is put in slowly and loosely, a 

 preliminary rapid fermentation takes place which heats the mass, 

 destroys the acid-forming bacteria, and excludes air. Fermenta- 

 tion then goes on more slowly, producing a sweet silage. Too 

 high a temperature would produce bad results. Sweet silage is 

 said to become moldy on exposure to the air, while acid silage is 

 relatively resistant to decay. The changes are due to the living 

 cell, and enzymes of the plant, as well as to bacteria. 



The following experiment shows the effect of temperature on 

 the silage. The volatile acid is chiefly acetic acid, the non- 

 volatile is lactic. 



The fermentation also converts some of the proteid nitrogen 

 into non-proteids, the action going so far as even to form a small 

 quantity of ammonia. 



A silo must be perfectly air-tight, or the loss resulting will be 

 great ; the walls must be rigid, the inner surface must be smooth 

 and uniform, and it should dry out quickly and completely. 



Losses in Silage Making. The loss in a silo depends upon its 

 construction, on the crop siloed, and on the amount of moisture 

 present. The loss is much lessened by proper construction of the 

 1 Bulletin 70, Connecticut Station. 



