212 BETTER DAIRY FARMING 



crop to fill it. Two things are important here. In the first 

 place, the silo must be large enough to hold a year's supply. In 

 the second place, the diameter of the silo must be small enough so 

 that enough will be fed off each day to prevent spoiling at the sur- 

 face. This means one and one-half to two inches in winter and 

 somewhat more in summer. 



366. Capacity of silos. — The following table can be used 

 in estimating the weight of silage at the time filling is completed, 

 and thus will show what size of silo must be built to hold a given 

 amount. The table is taken in a condensed form from Missouri 

 Circular 89 by Eckles. The figures assume that the silage is well 

 tramped down and that after settling two days the silo is refilled : 



367. Calculating the requirement. — Knowing the size of the 

 herd, the rate fed per day and the feeding period, the tonnage needed 

 is easily computed. A herd of 15 cows consuming 35 pounds per 

 day for 300 days would require : 



15x35x300 _ 



= 78. 8- tons 



2000 



By referring to the above table we see that a silo 14 feet in diam- 

 eter by 30 feet deep would hold 79 . 5 tons. The figures in the table 

 must not be relied upon too closely because the capacity of a given 

 silo in terms of tonnage will vary according to the condition of the 

 corn as it goes in and the method of filling. 



368. Calculating the acreage. — In determining the acreage 

 needed to produce the tonnage desired, the farmer must be guided 

 by his own experience as to what his land will produce. A good 

 crop of corn will yield 10 to 15 tons of silage to the acre. 



