As the article says most horses, especially pleasure horses not ridden for work purposes, can be fed a hay-based diet. If you have a hard keeper, a horse for whom weight just does not stay on, see your vet for the best diet alternatives. ~ HfH
According to the National Research Council’s Nutrient Requirements of Horses, most horses not participating in heavy work can maintain a healthy body condition score by being offered forage as the only source of calories, in addition to access to fresh water and a salt supplement. Here are some tricks for managing horses without supplemental calorie sources.
1. Weigh your horse’s hay based on your horse’s target body weight and ensure your horse is receiving 1.5–2.5% of its body weight in forage each day.
2. Have a veterinarian or equine dentist routinely examine and treat your horse’s teeth. Don’t assume the horse has a functional mouth if you simply pull back his lips and find a full set of incisors. These front teeth are usually the last ones lost by aged horses. The molars you don’t see grind forage. If your horse is not able to chew its hay sufficiently, consider cut hay as an alternative.
3. If the horse is overweight, restrict grazing and offer mature hay with a lower content of easily digestible sugars and higher indigestible fiber. However, be sure that the horse will actually eat it and not just use it for bedding.