Gastric Ulcers in the Horse

What are gastric ulcers?

Gastric ulcers are breakdowns of the stomach lining and are common in horses and foals. Equine Gastric Ulcer Syndrome (EGUS) is a multifactorial condition and is associated with a variety of clinical signs.

The horse’s stomach is divided into two distinct regions, the upper squamous region and the lower glandular region. For appropriate treatment, it is important to differentiate between squamous and glandular ulceration.


Areas of the Stomach


Diagram of Stomach


Pylorus – Ulcers

Equine Squamous Gastric Disease (ESGD) refers to ulcers that occur in the squamous region, and these make up around 80% of ulcers. The squamous region is susceptible to ulceration as, unlike the glandular region, it does not produce mucus secretions to protect against the acidic stomach contents. There are many risk factors for ESGD which mainly relate to diet and routine; these include a high concentrate/low roughage diet, stress, intensive exercise, and long periods with an empty stomach. ESGD is therefore more common in athletes, particularly racehorses, but can occur in any horse.

Ulcers in the glandular region occur less commonly and Equine Glandular Gastric Disease (EGGD) is not as well understood, but involves the failure of the protective mucus coating

What are the clinical signs?

The clinical signs of ulcers are very variable and there may be no signs at all. They are non-specific and often subtle. Adult horses may present for poor performance, reluctance to work, changes in behaviour, or discomfort on girthing. They may show signs such as decreased appetite, weight loss, poor condition, or recurrent colic. There is also an association between gastric ulcers and crib biting.

Clinical signs in foals can also include diarrhoea, intermittent nursing, teeth grinding, salivation and lying on their back. However, most foals do not show any clinical signs until the ulceration is severe so they should be investigated immediately to avoid complications such as perforation.

How are gastric ulcers diagnosed?

Veterinarians may suspect gastric ulcers based on the history, clinical signs, and clinical examination of a horse. To make a definitive diagnosis, a horse must undergo gastroscopy, where a camera scope is passed up the horse’s nostril and down the oesophagus into the stomach to visualise the lining. The oesophagus, squamous and glandular regions of the stomach, and first part of the small intestine can be evaluated. Any ulcers found are graded for severity; ESGD is graded 1-4 and EGGD is graded descriptively according to location and appearance. The procedure is minimally invasive, but the horse will be lightly sedated, and should be starved for a minimum of 12 hours beforehand.

The gastroscopy findings will always be interpreted with the clinical signs of the horse when deciding appropriate treatment and management. Horses will require repeat gastroscopy to monitor their ulcer healing before treatment is stopped.


Grade 1 – Hypekeratosis


Grade 2


Grade 3


Grade 4

How are gastric ulcers treated?

Once a horse has been diagnosed with gastric ulcers, a plan will be created to treat existing ulcers and prevent new ones from forming. This is achieved by decreasing acid production and protecting the stomach lining.

There are several drugs that can be used to treat and prevent gastric ulcers, which are administered orally.

  • Omeprazole: A proton pump inhibitor that blocks acid production. This is the most common treatment and is administered as a paste once daily. There are different dosing regiment depending on if you’re treating diagnosed gastric ulcers, or simply using as a preventative.
  • Sucralfate: A mucosal protectant that coats the lining and assists healing. Often used for EGGD in combination with omeprazole.
  • Ranitidine: A histamine-receptor antagonist that reduces acid production.
  • Misoprostol: A synthetic prostaglandin analogue. It is an alternative treatment for EGGD.

Other treatments and supplements may also be added, such as pectin-lecithin complexes which increase mucus concentration.

Management of the horse is also very important. Access to high quality forage and/or grazing should be increased, with turnout where possible. There should also be free access to fresh water 24 hours a day. Long periods without food should be avoided, for example by using a small holed hay net. The concentrate component of feed should be reduced to provide a low starch diet and any concentrate feeds should be split into more frequent smaller meals. Oils/fats can be added to the feed to provide an alternative source of energy, and certain oils such as corn or rapeseed oil may actually decrease gastric acid production. Around 30 minutes before exercise, the horse should be given a small handful of chaff, as this forms a barrier on top of the acidic stomach contents to reduce acid splash onto the squamous region. Stressors should be kept to a minimum and routines should be kept consistent whenever possible.

If you’re worried about gastric ulcers in your horse please don’t hesitate to give the clinic a ring today on (02) 4927 6135!

Thank You Randlab for the photos!