straw(redirected from draws straws)
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the dry stems of cereal and leguminous crops that remain after threshing; the dry stems of flax, hemp, ambary, and other plants whose leaves, flowers, and seeds have been removed. The straw of cereal crops is primarily used to feed cattle.
The chemical composition and nutrient value of straw depend on the plant species, the climate, and the methods of reaping, threshing, and storage. Straw contains 35–45 percent cellulose and other hard-to-digest complex carbohydrates, 2–6 percent protein (in leguminous straw, 4–9 percent), 1.2–2 percent fat, and 4–7 percent ash. One hundred kilograms of millet straw contains an average of 40 feed units and 2.3 kg of digestible protein; 100 kg of barley straw has 33 feed units and 1.3 kg of digestible protein. Spring straw has more protein and less cellulose than winter straw; hence, it has the higher nutritional value of the two types.
Owing to its low nutritional value and low digestibility, straw is used mainly to add bulk or as a supplement to rations that include a high proportion of succulent feed. Various methods of preparation are used to improve the edibility of straw, for example, grinding, steaming, flavoring, and treatment with chemicals (soda ash, lime, ammonia). The granulation of straw mixed with concentrates and artificially dried grass is becoming widespread.
Livestock may be fed all types of straw except buckwheat, which sometimes causes reddening of the skin, rash, and swelling of the joints. High-quality cereal straw is light in color, shiny, and resilient; straw that has lain for a long time is brittle and dusty and often has a spicy odor.
Straw may be used as litter for farm animals and as raw material in making adobe, insulating panels, and mats. Straw from flax, hemp, and other textile plants is the raw material used to obtain treated plant fibers, from which textile fibers are isolated.