Gastric Ulceration in Horses

What is the cause of gastric ulceration?

The equine stomach is split into two portions - the lower 'glandular' portion is designed to have food material and acid in it, and the acid part is used as part of the horse's normal digestion. The upper 'squamous' portion of the stomach has a different structure and is not designed to have acid sitting next to it. If you imagine that the horse's stomach is mainly filled with a 'soup' of liquid, chewed up hay and grain, with the hay and roughage normally sitting on top of the 'soup' to help keep it all settled flat and avoid it from splashing the upper portion of the stomach. When the horse gallops you can imagine the stomach contents splashing around and this is often when the acid gets a chance to damage the top part of the stomach and cause ulceration here.

In the photo opposite the white liquid represents the 'soup' of stomach contents, that sits in the bottom part of the stomach which is lined with the dark pink lining designed for this purpose. The paler pink top half of the stomach is not designed to have this soup sitting next to it, as it is not able to protect itself against the horse's acidic digestive juices. This stomach is normal, with no ulceration present.
One of the major reasons that TB's are so prone to stomach ulcers is because they have a diet of mainly grain, so often lack this protective roughage mat on the top of the soup in the stomach which reduces the acid splashing around the stomach when the horse exercises.

Some medications can also cause ulceration of the stomach and intestines, but this a slightly different syndrome usually related to the use of steroids and non-steroidal medications at a high dose or over long periods of time. It is not related to acid 'splashing' in the stomach as described above.

It is important that, although a lot of racehorses in training do suffer from a degree of stomach ulceration, most of these horses will resolve their ulcers once they are moved into a paddock and their diet consists mainly of grass and hay.

What are the signs of Stomach Ulceration in horses and foals?

In adult horses the signs can vary. In more severe cases the horses will avoid eating hard feed, preferring only roughage and can even show signs of colic after eating. Other horses will show more non-specific signs such as a dull coat, failure to maintain weight and loose manure.

This photo shows how that more fragile paler pink part of the stomach appears when it is ulcerated.

How can they be diagnosed?

There is only one way to definitely diagnose stomach ulcers in horses, and that is to pass an endoscope down into the stomach of the horse to assess the inside of the stomach lining.
This procedure is referred as 'gastroscopy". To do this the horse has to have been starved for around 12 hours beforehand, so that the stomach lining is not obscured by chewed up hay! The procedure is done under standing sedation and the endoscope is normally linked to a screen so that you will be able to see what is going on and ask the vet questions. Most horses tolerate the procedure very well.

What are the treatment options for stomach ulcers?

There is one medication which is often preferable to the others in terms of treating stomach ulcers. This is a medication called Omeprazole, which is the active ingredient in Gastropell and many other ulcer treatment products. This is a medication which reduces the acid production in the horse's stomach and so reduces the potential for the acid to cause ulcers. It also treats existing ulcers as well as preventing the production of new ones.

Management to reduce incidence of stomach ulcers

For horses that are prone to stomach ulcers, feeding roughage is very important. This is because the roughage sits on top of the acid and helps keep it where it should be in the stomach. Avoid exercising the horse immediately before and after a hard feed, when acid production is highest. If your horse can have a haynet available when you are out at a show to pick at, then it will reduce the chances of ulceration. In the long term, it is about feeding the hard feed at the right times and always with plenty of roughage and we are more then happy to help you with this if you have any more specific enquiries.