Soybean meal is the most important protein source used to feed farm animals. Its feeding value is unsurpassed by any other plant protein source and it is the standard to which other protein sources are compared.
Soybean meal is the by-product of the extraction of soybean oil. Several processes exist, resulting in different products. Soybean meal is usually classified for marketing by its crude protein content. There are two main categories of soybean meal, the high-protein soybean meal with 47-49% protein and 3% crude fiber, obtained from dehulled seeds, and the conventional soybean meal, with 43-44% protein, that contain the hulls. In solvent-extracted soybean meals, the oil content is typically lower than 2% while it exceeds 3% in mechanically-extracted meals.
Soybean meal is heat-treated during production, to denature the trypsin inhibitors of soybeans, which would otherwise interfere with protein digestions. Soybean mean is used for animal feeds, principally as a protein supplement, but also as a source of metabolizable energy. For instance, for rapidly growing lambs on low-protein feeds, soybean meal can be an important supplement to ensure adequate protein intake, and partly because of its palatability, soybean meal is often recommended for use in starter rations when creep feeding lambs.