For convenience, Table ill has been pre pared, showing the size of silo required for feed ing any number of cattle for a given time.
This table gives the number of cows in herd, and tonnage of silage, for both 180 and 240 days of feeding of 40 pounds of silage per cow; also acreage of corn estimated to fill the silo, and the dimensions of the silo itself. The diameters given are such that at least 2 inches in depth of silage will be taken off daily.
As stated above, the number of animals to be fed should determine the diameter of the silo, and the length of time silage is wanted should determine the height of the silo. The amount of silage to be fed per cow must be determined first. Decide whether each cow is to have 20, 30, 40, or 60 pounds per day. Then, having de cided this point, make the diameter of the silo such that by feeding the cows so much per day the silage can be fed down at least 2 inches per,, .rlay, as this will prevent moulding of silage. If a silo is made too large in diameter, and this is the most frequent error, one of two things will happen—First, the silage will be mouldy all the time, owing to the inability to feed it down rap idly enough; or, second, the cows. will be fed more than they should have in an attempt to keep ahead of the moulding.
Where large cows are kept, and it is expected to feed 40 or 60 pounds per cow daily, it fre quently happens that it is desirable to cut down the silage ration, It is well to have the diameter of the silo small enough so that the farmer can cut down the ration one-third or even one-half, and still be able to feed down the silage 1 to inches daily.
In the dairying sections, many farmers con sider this point so important that they are build ing two small silos instead of one large one, so that they can feed a light ration and still feed down the silage rapidly enough to prevent moulding. In the older dairying sections where silos have been longest in use and where dairy men have used up their first silo and are build ing a second time, they build two small ones in place of the one large one. They build smaller in diameter and higher.
About fifty cows seems to be the most that can be fed with advantage from one silo. In general, 40 pounds of silage is figured as the av erage daily feed of a cow.
For further convenience in figuring in con nection with the sizes and capacities of silos, Table IV is presented.
Silo of Concrete Blocks. The method used for the construction of a silo of this character is as follows: Place five eight-inch rods with turn buckles every four or five feet, the ends being down in the hollow block sufficiently to hold while tightening the turnbuckle. The lap or tie rods used around the entire circle at the same course of blocks, are made of half-inch rods. The jamb at the opening is made of 2 by 12-inch wood, with a 1 by 4-inch board set ting into the recess of the block to prevent slip ping, and two stops on the opening side for a sliding plank. A casing board on the inside is required only when the blocks have no recess. It may prove cheaper to build a silo of 2 by 6 inch studding, 16-inch centers, with metal lath and stucco plaster on both side and interior.
Construction of a Concrete Silo. The silo has come to be one of the necessary parts of the farm equipment, and it is unquestioned that concrete is the ideal material for its construc tion, for concrete makes the silo air-tight and too heavy to blow over, and it will last for ages. The concrete silo can be built at low cost, pro vided the walls are not made too thick. By using reinforced concrete, the thickness of the walls can be reduced to a minimum. Silos in cold climates are best built with a hollow wall. The specifications for one of this character are: Excavate to a depth below the frost line and of the desired diameter, allowing for the thick ness of the walls. Erect a sixteen-inch solid wall to the level of the ground with concrete, one part Portland cement, two and one-half parts clean, coarse sand, and five parts broken stone. After removing forms, fill the excava tion inside the walls to within 8 inches of the ground level, with cinders, gravel, or broken stone, and tamp hard. Pick with a stone ax that part of the inside wall that shows above the porous foundation, and wet thoroughly. Fill the space on top of the cinders, etc., with con crete, to within one inch of the foundation.
Erect forms four feet high for three-inch hollow core walls with ten-inch air-chamber.
In a circular form there are two sides, the inner and the outer. These are made in the same way, but cannot be of the same pattern, as the thickness of the walls comes between the two parts, making the radius of the sides dif ferent. The simplest way to make a circular form is to draw a circle of the size of the form desired and lay boards around the circumfer ence of the circle. These boards should be lightly tacked together in place, and, using the same measure, mark the circle on them. They should then be knocked apart and sawed out along the lines marked, the pieces then being fastened securely together. After making two or more circular forms, place them at equal dis tances apart, and put on the side boards.