50 Concrete Silos 



different considerations. The diameter of the silo will 

 be determined by the size and nature of the herd to be 

 fed, and the height by the number of feeding days per 

 year for which it is desired to provide. A common 

 error in building a silo is to make the diameter too 

 great for the size of the herd. When once a farmer has 

 removed the top layer from his silage and has com- 

 menced to feed from it, the silage should be removed 

 at the rate of not less than 2 inches in depth per day in 

 the winter time and 3 inches in the summer time. It 

 is necessary to establish a limit of this kind in order to 

 insure that none of the silage shall spoil. 



The weight of a cubic foot of silage varies according 

 to the pressure to which it is subjected, but there are 

 certain average figures which can be taken as suffi- 

 ciently accurate. For instance, in a silo 30 feet deep, 

 a cubic foot of silage will average about 40 pounds in 

 weight; so by knowing the amount of silage to be fed 

 daily, it is possible to estimate what the diameter of the 

 silo should be to permit the removal of a certain num- 

 ber of inches in depth each day. 



Table II, which is taken from Bulletin No. 21 of the 

 Association of American Portland Cement M'anufactur- 

 ers, shows the approximate minimum pounds to be fed 

 daily from the various diameters of silos. This is based 

 on winter feeding, and for summer feeding would, of 

 course, be about 50 per cent more, in order to keep the 

 silage in good condition. This table also shows the 

 number of animals which can be fed from each silo on 

 the amount taken 'away daily at a stated ration for 

 each kind of animal. Of course, many feeders will not 

 make out their rations according to this table ; but with 

 the help of the table, and substituting their own weight 



