Horses are grazing animals and their digestive system is able to take in large amounts of grass. The bulk of a horses diet should be a good quality hay and/or grass.
Other nutritional requirements include; grains, fresh water, salt, and minerals. How much you feed your horse depends on their weight, age, activity, and so on. Your veterinarian can assist you in implementing the appropriate diet for your individual horse. At our barn, horses are given hay and grain two times daily. Smaller, more frequent feedings are better if your schedule permits-some owners prefer three or even four smaller feedings per day.
The horses are also given free pasture daily as the weather permits. In addition, all are given constant fresh water and our horse has a mineral block in her stall. Some horse owners also give nutritional supplements in addition to their regular diet. Here is a great site that offers Nutri-Link performance, joint supplements, and vitamins. Nutri-Link has been providing quality nutritional supplements since 1988.