Gastric Ulceration in Horses – What Can We Do?

Consistent with the two different types of stomach lining, we divide equine gastric ulcers in squamous and glandular ulcers, depending on in which mucosal part we find them.

ESGD – Equine squamous gastric disease describes gastric ulcers in the squamous mucosa. They can develop relatively quickly when this part of the stomach lining comes into contact with gastric acid. There is always a pool of some fluid including stomach acid in the bottom of the stomach, even when a horse is not anticipating food or has just eaten. Without any protection of the top half of the stomach, as you can imagine, this acid would splash up during exercise of the horse. For this reason squamous ulcers are sometimes called ‘splash ulcers’ especially if we find them in a ‘splash’ pattern just above the margot plicatus which divides the lower (self-protecting) part of the stomach lining from the upper (unprotected) part of the stomach lining. One way to protect this upper part of the stomach lining is by feeding the horse constant fibre (hay, chaff etc) and especially before exercise, so that the ‘matt’ of fibre floats/sits on top of the stomach fluids and prevents splashing. Also, the increased production of saliva will in part buffer the stomach acid to be less acidic so less harmful to the unprotected stomach wall. Horses that have no access to fibre or do not eat it, especially right before vigorous exercise, are most at risk of developing these ulcers.

EGGD – Equine glandular gastric disease describes gastric ulcers in glandular mucosa. The glandular mucosa is the lining of the lower part of the stomach, where the stomach fluids and acid sit, produced by this glandular mucosa which also produces a gloopy substance sticking to the mucosa as a barrier for the acid, so the exposure of the mucosa itself to the acid is limited. Ulcers can develop in this area if the protective layer is not produced properly or is broken down. The exact mechanisms for this are unknown, but it is thought that lots of alfalfa or straw (very stalky fibre mechanically breaking the barrier down), bacterial balances in the stomach (bacteria breaking the substance down), certain drugs (chemical impact on the barrier) can be the cause for it breaking down, and that reduced blood flow through the stomach wall (due to certain medications, hormonal alterations or stress) could cause lesser production of this layer.