hay, wild or cultivated plants, chiefly grasses and legumes, mown and dried for use as livestock fodder. Hay is an important factor in cattle raising and is one of the leading crops of the United States. Alfalfa, timothy, and red clover are the principal hay crops. After mowing, the hay is left spread in the field or is stacked in windrows or in cocks for drying. It must dry quickly and uniformly; its nutritive value and palatability are reduced by overexposure to sunlight or rain, and unequal drying often results in loss of the leaves, which form two thirds of its feed value.