Horses are natural grass eaters. Their mouth structure and digestive anatomy allow horses to successfully use forages as a primary source of nutrition and as an important part of normal digestive system function. This requirement for forages is most easily supplied by pasture and hay. Mature horses will generally consume 2 to 2.5 percent of their body weight in feed each day. Ideally, horses should consume l percent or more (as dry matter) of their body weight daily as hay or pastures. Forages can provide varying amounts of the nutrient requirements depending on the forage quality and amount consumed. The remainder of the daily diet needs for a particular class, or production stage of horse is often provided in supplemental concentrates, minerals and vitamins.