Carey A. Williams, Ph.D., Extension Specialist in Equine Management FS #038  Revised: April 2004 Digestive System Limitations Horses are non-ruminant herbivores (hind-gut fermentors). Their small stomach only has a capacity of 2 to 4 gallons for an average-sized 1000 lb. horse. This limits the amount of feed a horse can take in at one time. … Continue reading The Basics of Equine Nutrition