Gastric ulcers in horses (also known as equine gastric ulcer syndrome or EGUS) are a common problem, particular among racehorses and elite competition horses, although horses of all ages and types can have them, particularly if they have limited access to forage. Foals are also susceptible, not least because they have relatively thin gastric mucosa.
Squamous gastric ulcers occur when the digestive stomach acids come in to contact with the upper part of the stomach lining, which does not have the same protective layer as the lower part of the stomach. Glandular ulcers affect the bottom two-thirds of the stomach, which is submerged below the acidic gastric juices.
It can be hard to interpret the significance of gastric ulcers in the horse, as some positive cases will have no definitive clinical signs and it is important to review the whole horse health picture and not just the ulcers themselves.
Causes of gastric ulcers in horses
In a natural environment the horse will graze for up to 16hr a day, so the acidity is reduced by the forage filling the stomach almost constantly, as well as by bicarbonate in the saliva that is produced as the horse chews.