Understanding Equine Gastric Ulcers

Equine gastric ulcers are common, affecting horses of all ages and breeds. These painful sores on the stomach lining are costly to treat and often recur. Prevention is essential to avoid gastric ulcers and prevent relapses after treatment.

Eating Like a Horse

The equine stomach has two parts:

• The glandular (lower) portion secretes stomach acid and compounds such as buffers and mucous to protect itself from the effects of being submerged in acid.
• The squamous (upper) portion does not release acid, so it does not have any protective mechanisms. It is at risk of becoming ulcerated if it contacts acid.

Horses have small stomachs and are built to eat continuously. In a natural grazing situation, a steady flow of acid is required for digestion, so the stomach produces acid around the clock. In a natural, high-roughage diet, acid is buffered by feed and saliva. When horses are fed twice per day, which is common in many boarding situations, the stomach is subjected to prolonged periods without feed to neutralize the acid. In addition, high grain diets produce volatile fatty acids that can also contribute to ulcer development. Physical and environmental stressors such as transport and stall confinement are additional risk factors.

Equine Gastric Ulcer Syndrome

Equine gastric ulcer syndrome (EGUS) was introduced as a term in 1999. As gastroscopy, which uses a small camera (endoscope) to examine the stomach, evolved it became clear that EGUS consists of two separate but sometimes concurrent conditions. In 2009, these were defined as equine squamous gastric disease (ESGD) and equine glandular gastric disease (EGGD). It is important to identify the type of ulcers present since treatment differs based on location.

Both ESGD and EGGD are highly prevalent and can occur in domesticated and feral horses. Whereas ESGD is caused by exposure to stomach acid, EGGD is linked to failures of the stomach lining’s natural defense mechanisms. Risk factors for ESGD include high starch intake and other feeding issues, extended periods (> 6 hours) without forage, and increased exercise intensity. Single housing, a high number of different handlers, and more days in work increase a horse’s risk of developing EGGD.

When to Suspect Ulcers

The most common clinical signs of EGUS are poor performance, disinterest in food, and behavioral changes. However, many horses show mild signs, and others are asymptomatic, showing no clinical signs at all.

Scoping Things Out

Gastroscopy is the gold standard for diagnosing EGUS. It is currently the only way to confirm the presence of ulcers and determine if a horse is suffering from squamous ulcers, glandular ulcers, or both.

Gastroscopy is generally an outpatient procedure, and results are available immediately. Horses must be fasted to ensure an empty stomach for optimal visibility. The procedure may be repeated during or after treatment to monitor healing and determine if additional treatment is necessary.

It is important to note that a “clean scope” (no ulcers found) still provides important information. It can help rule out gastric ulcers and allow your veterinarian to focus on other potential causes for your horse’s clinical signs.

Treatment: In It for the Long Haul

Equine gastric ulcers do not form overnight, and they don’t heal overnight either. Treatment typically lasts 1-2 months. Extended treatment may be required in some cases.

Omeprazole (GastroGard®) is the only FDA-approved treatment. It is highly effective for ESGD and may be used to treat EGGD in combination with sucralfate and misoprostol. Omeprazole alone has a poor success rate for treating EGGD.

Standard treatment involves 4 weeks of administering one syringe (per 1,250 lbs of body weight) ideally 30-60 mins before breakfast, followed by a preventive half-dose (or a tapering dose) for another 4 weeks.

These medications are available by prescription only. While compounded medications may seem more cost-effective, they are not regulated and may not contain the active ingredients at appropriate concentrations. This can lead to delayed healing and additional veterinary intervention, costing more in the long run.

Prevention is Key

Healing is not the end of the road. As management practices majorly contribute to the development of ulcers, without management changes, ulcers are likely to return.

Review your horse’s environment and routine. Look for ways to reduce stress, provide access to free choice forage, and plan meals and exercise appropriately.

UlcerGard®, which is the same as GastroGard® but administered differently (and available without a prescription) can be used for ulcer prevention during travel and competitions. It should start several days in advance and continue for a few days afterward.

Equine gastric ulcers are often complicated but can be managed with appropriate care and attention to underlying causes. Understanding your horse’s digestive system, feeding and exercise routines, environmental stressors, and treatment and management options can aid in prevention, recovery, and long-term plans. Work with your veterinarian to develop a plan tailored to your horse’s individual needs.