Treatment of Equine Gastric Ulcer Syndrome (EGUS) is fairly uniform, although numerous treatment modalities have been described in the literature.

GastroGard (Omeprazole paste from Merial Limited) is no different than Prilosec’s “purple pill” and just as effective for horses as humans. The paste is given to horses once daily for 28 days to treat gastric ulcers and can be used as a preventative at a half dose.

What Is Equine Gastric Ulcer Syndrome?

The term provides a general description of a spectrum of inflammatory and disruptive mucosal pathophysiology affecting tissues of the distal esophagus, stomach, and duodenal entrance. Approximately 80% of these lesions are found in the nonglandular squamous mucosa of the stomach, especially on the lesser curvature just proximal to the margo plicatus. However, other areas, such as significant portions of the squamous mucosa along the greater curvature and up into the fundus and the antrum or pylorus may also be involved.

Acid-induced duodenal ulceration in adult horses and foals is considered part of EGUS. It is unknown whether duodenal ulceration, perforation, and stricture develop as a result of enteritis (duodenitis) or peptic factors. We do know, however, that in the presence of a stricture, gastric and esophageal ulcers are often severe. This article will deal solely with EGUS in mature horses.

EGUS is found more commonly in racehorses, with up to 90% experiencing symptoms, compared to 60% of other performance horses. A British study found that 22.2% of feral horses had equine squamous gastric disease (compared to 60.8% of domestic horses) and 29.6% of feral horses had equine glandular gastric disease (compared to 70.6% of domestic horses).

What Causes EGUS in Mature Horses?

The reason the incidence of EGUS has increased can be attributed to lifestyle changes. Horses evolved to constantly eat small portions, so their production of gastric acid is continuous. If sufficient food is not present, the digestive tract is susceptible to damage.

Instead of grazing all day, most of today’s performance horses are left inside a stall and fed measured meals 2 to 3 times a day. Since saliva is only secreted when the horse is chewing, it can’t buffer the continuously-produced gastric acid.

To make matters worse, performance horses are typically fed grains high in carbohydrates, resulting in an increase in the production of gastric acid and a reduction in the production of saliva. Large amounts of high-carbohydrate food pass through the stomach and large intestine before being adequately processed. As a result, lactic acid and gas are produced, pH levels are lowered, and gut dysbiosis occurs, leading to increased risk for hindgut acidosis, colic, and ulceration.

Other factors affecting performance horses include:

• Strenuous exercise, which may increase acid production
• Stress from transportation, feeding schedule delays, isolation, and exercise, which may increase acid production
• Use of NSAIDS, which reduce blood flow to the gastrointestinal tract and cause decreased production of the mucobicarbonate matrix by the gastric glandular mucosa

Diagnosis of Equine Gastric Ulcers

Adult horses with ulcers display nonspecific symptoms, which may include:

• Poor appetite
• Mild weight loss
• Poor body condition
• Low-grade colic
• Decreased performance
• Reluctance to train
• Rough or dull coat
• Excessive recumbency
• Aggressive attitude changes
• Girth sensitivity
• Teeth grinding or cribbing
• Excessive tail wringing

A video or fiberoptic endoscope must be used for a definitive diagnosis. There are barriers: Some ambulatory veterinarians do not possess the 3-meter endoscope required for diagnosis, and some owners are concerned about the cost of diagnosis.

However, when it comes to the horse’s health, investment in this diagnostic tool and in diagnostic services are a necessity. A definitive diagnosis dictates what treatments will be most effective for the horse.

Additional Information You May Find Helpful

Covetrus is not only your source for clinic supplies, we provide information on topics of interest, webinars, and more. Here are a few of our blogs specifically for veterinarians with equine clients:

EPM Treatment and Diagnosis

Navicular Syndrome New Treatment Option

Your Covetrus representative can provide other tips and suggestions of value to you and your clients! Contact us at: 855.724.3461 or online.

Sources:

https://aaep.org/horsehealth/equine-gastric-ulcer-syndrome

http://www.merckvetmanual.com/digestive-system/gastrointestinal-ulcers-in-large-animals/gastric-ulcers-in-horses

http://www.thehorse.com/articles/36028/gastric-ulcer-prevalence-in-feral-domestic-horses-compared

http://www.vetmed.ucdavis.edu/CEH/local_resources/pdfs/pubs-Oct2012-sec.pdf