SILAGE (from silo, Sp. silo, silo, from Lat. Rims, from Gk. atmic,siros, cetp6e, seiros, pit for corn), or ENSILAGE. A general name applied to green crops packed and preserved under pressure in specially constructed chambers (silos) or in stacks (stack silos), in each of which they un dergo fermentation. The preservation of green crops in silos possibly commenced about the year 1800, and in the United States about 1875, since when the use of silage has greatly extended. The first silos made in the United States were of stone or brick. thick-walled and lined with a smooth coat of cement. Since these were ex pensive, wooden silos were tried, and were found to give satisfactory results at much less cost. Silos should be deep with smooth walls, with as few corners as possible, preferably round or square, and to be more efficient should be as near ly air-tight as practicable. If made of wood the walls may be covered with gas tar.
A cubic foot of silage under average condi tions will weigh 35 to 40 pounds. Ordinarily, this amount with other food is enough for one cow's daily ration, and at this rate one cow will consume about 4 tons in 200 days. Allowing for waste and emergency conditions, 50 tons is con sidered necessary for a herd of 10 cows for 200 days. For a round silo, 30 feet deep, King gives the following dimensions for herds of different sizes, estimating 5 square feet of surface silage for 1 cow: The plants most available for silage in the United States are Indian corn. red clover, rye. oats, wheat, sorghum, the millets, alfalfa, soy beans, and cow-peas. Corn is considered most satisfactory. The entire plant should be siled, the best time to cut this and other crops being at maturity before the leaves turn brown or the water content begins to diminish. Corn fodder should be cut into pieces one or two inches long when the silo is filled, otherwise the stalks do not pack closely and are not convenient to handle. Silage should be well distributed and well packed along the sides and in the corners. if cut in a very dry season and not very juicy, considerable water should be poured on the silage after the silo is filled. After filling, some per sons prevent waste from the spoiling of the top layer by feeding at once. Others place 6 inches to 1 foot of chaff or cut straw on the silage to prevent decay, still others place a layer of tarred paper smoothly over the surface before piling on the straw.
When green materials are ensiled various changes take place. A portion of the carbo hydrates, and to a less extent the albuminoids, of the plant is broken down and acids and other simple bodies are formed. At the same time, oxygen is absorbed and carbon dioxide is pro duced. These changes result in a loss of ma terial which ranges from 4 to 40 per cent. of the total amount originally present. The chemical changes are accompanied by the production of heat, the temperature sometimes rising as high as 66° Centigrade.
Generally speaking, 3 tons of silage are equal in feeding value to 1 ton of hay. On this basis
a much larger amount of digestible food can be secured from an acre of silage corn than from an acre of hay. The food equivalent to 4 tons of hay can easily be produced on an acre of land planted to corn. Crops may be more compactly and economically stored as silage than as hay. A silo of ISO tons capacity will contain silage equivalent to 54 tons of dry matter in the same space. Less than 23 tons of led clover hay, con taining less than 20 tons of dry matter, can be stored in the same space in a barn.
Consult: Plumb, Silos and Silage, United States Department Agricultural Farmers' Bulle tin 32; Thurber. Silos and Ensilage (New York, 1886) ; Bailey, Ensilage (New York, 1881) ; Col lingwood, Conserved rattle Food (New York, 1892) : Cook, Silo and Silage, Michigan Experi ment Station Bulletin 90, ser. 6; Mills, Silos, En As shown by analysis, the cured silage does not differ materially in composition from the green crop. It is therefore essentially coarse fodder. Silage from legumes is naturally richer in pro tein than that from corn or other cereals. In some of the mixtures, notably Robertson's silage mixture, the attempt is made to approximate more nearly a balanced ration than is the case with either material alone. Corn silage has the following average coefficient of digestibility: Dry matter, 70.8; protein, 56.0 ; fat, 82.4; nitrogen-free extract. 76.1; crude fibre, 70.0; and ash, 30.3. Cow-pea silage: Dry matter, 59.6; pro tein, 57.5; fat, 62.6; nitrogen-free extract. 72.5; crude fibre, 52.0; and ash. 30.3. As regards di gestibility silage compares favorably with the green crop from which it is made or the corre sponding dry fodder.
The first general use of silage as a stock food was with dairy cattle. The extensive erection of silos in many parts of the United States, how ever, has resulted in its adoption by many feeders of horses, sheep, and beef cattle. Animals usual ly eat sound silage with a relish, and reject it only when decay is present. For milch cattle it seems especially well adapted, and the silo has proved an important and economical addition to the dairy farm. Dairy cattle should he fed rela tively small amounts of silage until they be come accustomed to it.. In changing from grass or dry feed to silage, if a regular ration is given, the silage will perhaps slightly affect the taste of the milk for a few milkings, and if the change is from dry feed it may cause too great activity of the bowels. Its use as a food for swine has not been found successful at the agricultural ex periment stations.
silage, and Silage (New York, 1S95) ; Woods, Ensilage—Its Origin, History, and Practice (Nor wich, England, 1883) ; Hand Book of Experiment Station Work, United States Department Agricul ture, Office of Experiment Station Bulletin, No. 15; King, Silage and the Construction of Modern Silos, Wisconsin Experiment Station, Bulletin S3: Conn. Agricultural Bacteriology (Philadel phia, 1901).