CATTLE FOODS NATURAL PRODUCTS 235 



food substance by fermentation and an unnecessary 

 handling of many tons of water contained in the green 

 material, with no compensating advantages. But any 

 crop used for the production of silage should be managed 

 in the most efficient manner. A few general facts may 

 be discussed in this connection. 



321. Construction of silos. Silos that are of proper 

 construction and shape have air-tight perpendicular 

 walls and a height considerably in excess of either of 

 the horizontal dimensions. These conditions are essen- 

 tial to the completest possible exclusion of air and to 

 the closest possible packing of the material, with a mini- 

 mum of exposed upper surface. 



Silos may be either round, square, or rectangular, 

 provided that in the latter case one horizontal dimen- 

 sion is not too greatly in excess of the other. The shape 

 of a silo which is most economical and efficient is not the 

 same for all conditions, although the round and square 

 forms hold most in proportion to the wall area. Many 

 farmers desire to have the silo in the barn, and generally 

 there the square or rectangular form is more economical 

 of space than a round one. When built outside the barn, 

 the round form, according to the opinion of many, may 

 be used to advantage both as to expense and results. If 

 a square or rectangular silo is built the corners should 

 be cut off inside in order to prevent an access of air and 

 the decay which occurs at those points when this is not 

 done. Several kinds of materials have been used suc- 

 cesfully in building silos, wood, brick, and stone. If the 

 walls are of masonry the inner surface must be cemented 

 not only air-tight but so smoothly as to allow easy and 

 uniform settling of the silage without leaving air spaces. 

 If wood is used, which is the more common material, the 



