T//E CONSTRUCTION OF MODERN S/tOS 



773 



silos in preference to one very large one. With very large CHAP, 

 silos too much surface of silage is exposed while feeding ; and, XVI ' 

 if the height is increased to modify the surface dimensions 

 beyond a reasonable limit, excessive labour is involved in the 

 working. With rectangular silos the difficulty can be obvi- 

 ated by having one or more partitions dividing the silo into 

 two or more square, or nearly square, compartments. The 

 height above ground should not exceed 20 to 25 feet, and 

 the depth under ground should not be more than 5 or 6 feet, 

 the limit from which a man can conveniently lift the forage. 

 Whatever form is adopted for the silo, it should always be 



Fig. 242. — Filling twin tub-silos, Australia. 



built with a greater capacity than would be necessary it it 

 could be filled at once to the top with good silage, as con- 

 siderable allowance has to be made for waste from settling 

 and from spoiled silage. Even if material is added a second 

 or third time there will still be a certain amount of waste 

 space to be allowed for. One-fifth is considered a low estimate 

 for loss of space and waste silage. 



746. Capacity. — As a basis on which to ascertain the size 

 of silo necessary to hold food for a certain number of cattle 

 for a certain period of time, 40 lbs. may be taken as the 

 average amount of silage required to feed one animal per 

 day, and 40 lbs. may also be taken as the average weight of a 

 cubic foot of silage. Therefore, if the number of animals is 



