: 
HAY AND GREEN FEED 59 
usually cylindrical structure or building. In this is placed 
the forage usually as it comes from a cutting machine. 
The material is packed tight by tramping in order to 
exclude as much air as possible. If necessary, water is 
added to facilitate the packing. If properly prepared the 
silage or ensilage will keep for many months. The material 
is canned on a gigantic scale though it has not been steril- 
ized. More or less fermentation takes place but not of a 
character to interfere with its feeding value, nor with its 
palatability for stock that has become accustomed to the 
the characteristic taste of silage. If the packing of the 
silo has been done carelessly the material rots and is 
worthless. 
~ The silo is built tall and narrow in order to give greater 
pressure, thus packing the silage more closely. Further- 
more, the smaller surface exposed at the top gives less 
opportunity for spoiling. The top layer exposed to the 
air rots and must be discarded, unless the feeding is com- 
menced as soon as the silo is filled. The top layer may be 
of chaff or other material of little value. If there is a leak 
in the silo the silage will spoil at this point. The silo may 
be made of cement, brick or any other building material, 
but because of the lower cost is usually made of wood. It 
should be at least 24 feet high to give the necessary pres- 
sure and bulk. 
The silage should be fed rapidly enough to prevent the 
exposed upper layer from having time to spoil. For this 
reason it is not expedient to feed less than ten cows. It is 
essential to pack the silage tightly as it is placed in the 
silo. This forces out most of the air. The fermentation 
uses up the small amount of air remaining and if there are 
no leaks the fermentation ceases. 
Any kind of forage may be preserved in a silo, but the 
