Horses are not ruminants, but still can live off of plant material. Horses are grazing animals with digestive tracts best suited for eating forages for 15- 20 hours per day. Grass and hay are the natural feeds for horses due to the structure and shape of the equine digestive tract. Unlike the cow, their stomachs are relatively small and can only hold about eight quarts. Their stomachs can actually hold more, but the stomach begins to empty when it is only two-thirds full.