Horse Ulcers: Could a Simple Blood Test Help Diagnose EGUS?

Gastric ulcers in horses—collectively known as Equine Gastric Ulcer Syndrome (EGUS)—are surprisingly common. Yet many owners are unaware their horse may be affected, especially since symptoms can be subtle or entirely absent. Until now, the gold standard for diagnosing horse ulcers has been a gastroscopy (endoscopy of the stomach), which allows direct visualisation of ulcerated areas in both the upper (squamous) and lower (glandular) regions of the stomach.

Horse ulcers blood test

However, gastroscopy comes with its challenges: it’s expensive, requires fasting and sedation, and sometimes fails to reveal certain stomach areas like the pylorus. That’s why researchers are exploring easier, more cost-effective ways to detect horse ulcers—such as blood tests.

One promising indicator is GGT (gamma-glutamyl transferase), a blood enzyme already measured in routine equine blood panels. French researchers recently evaluated whether elevated GGT levels could indicate the presence of glandular ulcers in horses.

What the Study Found

A group of 59 horses, many showing classic symptoms of ulcers such as:

  • Teeth grinding
  • Picky eating
  • Mild colic
  • Girth sensitivity
  • Poor condition

…were assessed in the study. Blood samples were taken to measure GGT levels, followed by a gastroscopy after a 19-hour fast.

Surprisingly, a large percentage of horses without any obvious signs also had ulcers—80% of asymptomatic horses had squamous ulcers, and 37% had glandular ulcers. In horses showing symptoms, 79% had squamous and 48% had glandular ulcers. These findings highlight a critical message: just because your horse isn’t showing signs doesn’t mean they’re ulcer-free.

Horses with glandular ulcers had notably higher GGT levels (28.2 IU/L) than those without (9.7 IU/L). While this might sound promising, the proposed GGT cutoff value of 21 IU/L still falls within the “normal” range for most horses, making it difficult to rely on this test alone for diagnosis.

Why Gastroscopy Is Still Essential

While GGT levels could provide a useful clue, gastroscopy remains the most reliable diagnostic tool for equine ulcers. It’s the only method that allows your vet to see exactly what’s going on inside your horse’s stomach and determine the type and severity of ulceration.

That said, research into non-invasive diagnostic tools like blood markers is vital. The ability to screen horses more easily—especially those who are asymptomatic—could reduce delays in treatment and help monitor healing progress without repeat scoping.

Managing Horse Ulcers: A Whole-Horse Approach

If your horse has been diagnosed with ulcers—or you suspect they might be at risk—it’s time to take a full-circle look at their lifestyle and environment. Glandular ulcers, in particular, can be difficult to manage and are often influenced by more than just feeding routines.

To promote good gastric health and support ulcer recovery or prevention, consider the following:

✅ Ensure continuous access to forage – avoid long periods without food
✅ Reduce stress by maintaining consistent routines and minimising environmental changes
✅ Limit starchy feeds and break grain into smaller, more frequent meals
✅ Add gastric buffers and fatty acid supplements to help support the stomach lining

Supporting Training and Recovery with Rider Guider

At The Rider Guider, we know how vital it is for your horse to feel well—mentally and physically—during every ride. That’s why our audio training guides and dressage caller features are built with welfare in mind. Whether you’re managing ulcers or simply trying to keep your horse feeling their best, our flexible app helps you train smarter, not harder.

👉 Explore the App Here
👉 Try a Free Trial
👉 Learn More About Equine Wellness

Final Thought

Horse ulcers are more common than many think—and they don’t always come with obvious signs. While blood tests like GGT show promise, gastroscopy remains the most accurate diagnostic tool. If your horse is showing behavioural changes, girthiness, or performance issues, don’t ignore the signs.

Early detection and a whole-horse management approach make all the difference.