Tips for Preventing Equine Gastric Ulcer Syndrome

What can you do to protect your horse’s sensitive stomach against gastric disease?

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horse eating from slow-feed hay net
The fiber in hay increases saliva production when the horse chews, which has a buffering effect on stomach acid. | Photo: iStock

Equine gastric ulcer syndrome (EGUS) refers to horses with lesions or defects in the surface of the stomach lining. When ulcers occur in upper region of the stomach due to stomach acid splashing on the sensitive lining, the condition is referred to as squamous disease, whereas ulceration of the lower region of the stomach is referred to as glandular disease. While both glandular and squamous ulcers occur in the same organ—the stomach—this is where the similarities between the two gastric diseases end.

“Squamous and glandular disease are two distinct disease processes with completely different causes and risk factors,” explained Ben Sykes, BSc, BVMS, MS, MBA, Dipl. ACVIM, PhD, FHEA, a veterinarian, gastrointestinal disease researcher, and associate professor in equine medicine at Massey University, in New Zealand. “I think of them as the odd couple. Although they might share the same ‘apartment,’ they actually have very little in common.”

Risk factors for squamous disease are vast and varied, including stabling, transport, and duration of exercise at a trot or faster. Nutritional risk factors, such as inadequate roughage and excess carbohydrates, are also well described and the most important contributors to squamous ulceration.

“In contrast, one of the biggest risk factors for glandular disease, aside from breed with a clear predisposition present in Warmbloods, is frequency of exercise,” said Sykes. “Show horses exercising six to seven days per week are approximately 3.5 times more likely to have glandular disease than those exercising five days a week or less. Similarly, racehorses working five to seven days per week are 10 times more likely to have glandular disease than those working four days or less, independent of other factors.”

An increased number of handlers and riders is also a risk factor for glandular disease, emphasizing the importance of behavioral stress.

Signs of gastric ulcers can include the following:

  • Colic (abdominal pain)/postprandial (occurring after a meal) discomfort.
  • Weight loss or a picky eater.
  • Behavior changes.
  • Poor performance.

These signs, however, are not pathognomonic (indicative of a specific problem) for EGUS, and gastroscopy must be performed to diagnose the condition. The costs associated with scoping, treating, and monitoring response to gastric ulcer treatment can be high.

“Depending on whether the veterinarian comes to your farm or if you go to a clinic, a single gastroscopy can cost anywhere between $400 and $1,000,” said Kate Hodson, DVM, owner of Hodson Veterinary Services LLC, in Hebron, Indiana. “Some horses only need two scopes—one before treatment to confirm gastric ulcers and one after to show the healed portion of the affected area(s)—whereas other horses can be scoped three or more times before we finally reach the desired outcome.”

For this reason, it’s better and more cost-effective to focus on EGUS prevention.

“This is particularly true for glandular disease which, once established, can be difficult to treat and keep away,” said Sykes.

Here are some tips for preventing EGUS. Although this condition encompasses both squamous and glandular disease, it’s important to recognize they can coexist in the same horse.

Preventing Squamous Disease

Feed frequent meals “Ideally, horses at risk of squamous disease should be offered roughage (hay or haylage) ad libitum.” Said Sykes. “If that isn’t possible, then they should be fed three to four roughage meals per day. We have data that say horses fed roughage three or four times a day are nearly 20 times less likely to have squamous disease than horses fed roughage only one or two times a day.”

Fiber increases saliva production when the horse chews, which has a buffering effect on the stomach acid. Additionally, the chewed forage “ball” creates a splash guard in the stomach, limiting the splashing of stomach acid from the lower region of the stomach onto the squamous region.

From a practical standpoint, however, feeding frequently is challenging for many owners.

“For owners working full-time jobs and who have their horses at home or at boarding facilities, this may be challenging,” Hodson said. “Some boarding facilities will not offer additional feedings even with additional fees because they simply don’t have the workforce available.”

Offer adequate forage Horses should be offered at least 2% of their body weight in forage per day, and they should consume that forage over the course of the day.

“Using slow-feeding haynets to maintain the 2% intake will extend the horse’s feeding period without allowing the horse to become overweight or obese,” said Sykes. “In metabolically efficient horses it is better to choose lower-nutritional-quality hay and favor maintaining total intake than opting for smaller feeds of very calorically dense hay.”

Include alfalfa in the ration “For squamous disease, alfalfa is the hay of choice in terms of buffering capacity. It’s better than grass hay in that aspect,” said Sykes.

Fibrous, stalky alfalfa is also better than soft, leafy hay at forming the protective fibrous “ball” needed to stop acid splash, he said.

Sykes recommended feeding alfalfa hay strategically: “Rather than feeding at mealtimes, offer it very first thing in the morning to break the overnight fast and before exercise to help buffer the stomach acid and create a splash guard when it is needed most.”

But, he warned, “do not feed alfalfa as the sole forage. An alfalfa-only diet is not balanced.”

Permit access to pasture Allowing horses access to stalky, fibrous pasture grass that requires chewing will stimulate saliva production and help buffer stomach acid. Additionally, pasture is a source of short-chain omega-3 fatty acids, which might have an anti-inflammatory effect scientists believe benefits the stomach’s glandular mucosa.

“Pasture is more than just food in the horse’s stomach,” said Sykes. “It’s a combination of food, natural omega-3s, reducing management-related stress, and allowing horses to behave naturally, cohabitating with other horses.”

With pasture access, however, we must take the horse’s general health into consideration, limiting pasture consumption in horses with endocrine disorders such as equine metabolic syndrome.

Preventing Glandular Disease

“I say that squamous disease is 20% horse and 80% management.” said Sykes. “This means that most disease is caused by how we manage the horse. In contrast, glandular disease is 80% horse and only 20% management, where individual horses are predisposed to the disease and our ability to reduce risk via management is a lot lower.

“Diet, for example, isn’t an important primary risk factor in glandular disease like it is in squamous disease,” he continued. “As a result, our ability to impact disease risk via diet is much lower in glandular disease than it is in squamous. Instead, focusing on behavioral aspects such as rest days and environmental optimization is important.”

Give horses rest days A key risk factor for glandular disease is exercising four to five or more days per week.

“To help prevent glandular disease, allow horses two to three rest days per week,” said Sykes. “We don’t yet know if these rest days should be together or spaced out, but if the horse is actively training, alternating training and rest days is a reasonable approach.”

Minimize number of handlers/trainers/riders “An increased number of people handling or riding the horse is another risk factor for glandular disease,” he said. “What it really tells us is human-animal bond is important, and horses are creatures of routine. To help prevent glandular disease, try to create a stable and predictable routine for at-risk horses.”

In addition, focus on environmental enrichment.

Reduce your horse’s stress “Allowing horses pasture turnout with other horses for the socialization aspect is likely to reduce glandular disease risk as well as being important for welfare, because horses are herd animals,” Sykes said.

Certain types of music might also help, with results from one study showing something as simple as playing classical music resulted in more relaxed horses (Huo et al. 2021). When the researchers played classical music, the horses’ frequency of hay ingestion increased whereas the frequency of standing alert decreased, which is likely to help both squamous and glandular disease.

“Massage has also been shown to reduce stress levels in horses and is a simple thing to add into a horse’s regular management,” Sykes said.

Take-Home Message

Dietary management is key to preventing squamous disease, whereas rest days, consistent handling, and time with other horses are important for preventing glandular disease. For show horses at risk of developing both glandular and gastric disease, carefully address both horse and management factors to keep EGUS at bay.


Written by:

Stacey Oke, MSc, DVM, is a practicing veterinarian and freelance medical writer and editor. She is interested in both large and small animals, as well as complementary and alternative medicine. Since 2005, she’s worked as a research consultant for nutritional supplement companies, assisted physicians and veterinarians in publishing research articles and textbooks, and written for a number of educational magazines and websites.

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