SIXTH ANNUAL YEAR BOOK — PART VIII. 7 5^ 



Simply the springing of the sides of the silo allowed the air to gain 

 access to the silage to such an extent that the entire fifty tons spoiled 

 completely. Since for mechanical reasons it is practically impossible to 

 build a square wood silo with perfectly rigid walls, the round silo ib 

 the only proper form. 



Silage has been put up at the University for the past seventeen years. 

 The first silos were square and built inside the barn. These were made 

 of two thicknesses of % inch flooring with paper between. After having 

 been used seven or eight years the double walls began to show signs of 

 decay, and after nine years the walls were so badly rotted that the 

 silo was useless. If silos are to be built of wood the wall should be of 

 but one thickness. The difficulty with double walls is that moisture 

 gets in between the two layers of wood and as it does not dry out readily, 

 decay follows rapidlv. 



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PROPORTIOX AND CAPACITY OF SILOS. 



To obtain satisfactory results, silage must be in perfect condition 

 when fed. Since fermentation soon takes place when silage is exposed 

 to the air, the silo should not be of too great diameter. Not more than 

 eight square feet of surface should be allowed for each cow in winter, 

 then, when feeding 40 pounds of silage per cow, a layer about li/4 inches 

 deep would be fed off daily. When silage is fed in summer it is advis- 

 able that the exposed area be not over half this size so that a layer 

 three inches deep may be used daily. How^ever much stock is to be fed, 

 a silo 20 to 22 feet in diameter is as large as should be built. If a silo 

 is of greater diameter than this, much of the silage is at too great dis- 

 tance from the door, increasing the labor of removal. 



The deeper the silo the greater the pressure and the more compactlj- 

 will the silage be pressed together, hence the larger the amount that can 

 be stored per cubic foot. For example, a silo 20 feet in diameter and 40 

 feet deep will hold twice as much as one of the same diameter and 25 

 feet deep. This shows the economy of reasonably deep silos. To be 

 well proportioned the height should not be more than twice the diameter. 

 No silo should be less than 30 feet deep and to get sufficient depth for a 

 silo not over 12 feet in diameter, it may be placed 4 or 5 feet into the 

 ground. 



The number of tons of silage needed can readily be estimated from 

 the size of the herd and the amount to be fed daily. Even where it is 

 desired to feed as much silage as possible not more than 40 pounds 

 per cow should be fed daily. In Illinois, silage will usually be needed 

 from about October 20 to May 10, or 200 da3-s. Each cow should have 

 an allowance then of 200 times 40 pounds which is 8,000 pounds of 

 silage, or four tons per cow for the year. A herd of ten cows will require 

 a silo holding 40 tons; a herd of 30 cows 120 tons; 50 cows 200 tons; 

 and 100 cows 400 tons. Where young stock is raised an allowance 

 should be made for them. From the amount of silage needed the dimen- 

 sions of a silo of the required capacity may be determined from Table 

 1, which gives the capacity in tons of silos of different diameters and 



