Gastric Ulcers in Horses
By Dr. Shelby Krywonos, DVM
If you’ve spent any time around horses, you’ve likely heard about gastric ulcers. This condition has been studied for over two decades, and while we’ve made great strides in understanding and treating it, ongoing research is still needed.
Equine Gastric Ulcer Syndrome (EGUS) is a painful disorder affecting the lining of the horse’s stomach. It impacts not only the horse’s health but also its behavior and performance. In this article, we’ll explore the two types of gastric ulcers, what causes them, how they’re diagnosed, and current treatment options.
Prevalence of EGUS
The prevalence of gastric ulcers varies greatly depending on the group that was sampled and their exercise regime. For example, gastric ulcers are especially common in Thoroughbreds and Standardbreds—not necessarily due to breed, but because of their training and management. In some studies of thoroughbreds, the prevalence of gastric ulcers is 37-52% and increases to 100% once those horses are in training. A UK study showed a 71% prevalence in domesticated horses, compared to just 30% in feral horses. Exercise and management are significant risk factors for developing gastric ulcers.
Types of Gastric Ulcers
The horse’s stomach has two distinct regions:
- Squamous region (upper third)
- Glandular region (lower two-thirds)
Squamous ulcers are the most common and result from prolonged exposure to stomach acid. Unlike the glandular region, the squamous lining isn't well-equipped to handle stomach acid. Exercise or travel on an empty stomach can cause acid to "splash" into this area, irritating the tissue. Fortunately, these ulcers are the easiest to prevent and manage.
Glandular ulcers, on the other hand, are less understood. They likely involve a complex interplay of stress, exercise, the microbiome, and other factors. These ulcers often require longer treatment and additional medications. This is why it is important to perform a gastroscope to diagnose the type of ulcer present and to confirm that the ulcers have resolved after treatment. If we just treat horses for 28 days without looking we could very well be neglecting these glandular ulcers that require longer courses of medications.
Diagnosis: How Do You Know If a Horse Has Ulcers?
Clinical signs can be vague and mimic other conditions like back pain, ovarian issues, or sacroiliac discomfort. Common symptoms include:
- Girthiness
- Sensitivity to grooming
- Tail swishing
- Teeth grinding
- Behavioral changes under saddle
- Recurrent colic
Gastroscopy is the only definitive diagnostic tool. The procedure involves sedating the horse and using a long camera (scope) inserted through the nose into the stomach. Horses must be fasted to allow full visualization. Squamous ulcers are graded, while glandular ulcers are described based on their appearance. Photos are often taken to track healing.
Treatment Options
The mainstay of treatment is omeprazole, a proton pump inhibitor that reduces stsomach acid production and thereby increases the pH of the stomach. However, not all omeprazole products are created equal. The approved equine product available in North America is Gastrogard (made by Boehringer Ingelheim).
Sucralfate is often used alongside omeprazole. It acts as a protective barrier over ulcers, shielding them from further acid damage.
Gastrogard vs. Compounded Omeprazole
You may hear people refer to both “omeprazole” and “Gastrogard.” So what’s the difference?
- Gastrogard is the name-brand, equine approved formulation of omeprazole. A significant amount of research and effort went into this product to make it specifically designed to survive stomach acid and be absorbed in the small intestine. See, omeprazole must be absorbed by the body first and then it takes effect reducing the acidity of the stomach. If it is destroyed in the stomach, it cannot achieve this goal.
- Compounded omeprazole is created by various pharmacies and compounding companies. It lacks the protective formulation of Gastrogard, so much of the drug is destroyed before absorption—making it much less effective. Numerous studies have shown this.
Gastrogard Guarantee: Boehringer Ingelheim stands behind their product. If your horse is treated with Gastrogard for 28 days and still has squamous ulcers, they’ll provide another 28 days of treatment for free.
Management and Prevention
Since squamous ulcers are mainly caused by acid exposure, prevention focuses on dietary and lifestyle adjustments. Reducing exercise and increasing rest days has shown to be helpful for glandular ulcers.
- Feed forage little and often and feed a small amount of hay before exercise. This will combat gastric acid splashing up into the squamous region.
- Reduce grain and high-starch concentrates in your horse’s diet. Concentrates increase the acidity of the stomach. If a horse has high energy requirements, consider adding oil to their diet.
- Limit exercise above the trot to <40 minutes/day
- Provide 2–3 rest days per week
- Minimize stress: reduce transport, competition, and handler changes
- Be mindful that blankets irritate horses
- Use a preventative dose of Gastrogard (1/4 tube) during times of stress like travel or competition.
Supplements for Ongoing Support
Several supplements may help maintain stomach health and reduce ulcer recurrence:
Pronutrin (Equitop) – Available in Canada, it contains lecithin and fiber to support the stomach lining.
Secure Guard Gold – A pelleted supplement shown to support horses with chronic ulcers, digestive issues, and recurrent colic. The company even offers a colic guarantee: reimbursement is available for medical or surgical colics in horses fed the product.
KER RiteTrac - Neutralizes excess gastric acid, protecting the stomach lining and restoring the normal gastric environment
References