Rather than repeatedly treating horses for equine gastric ulcer syndrome (EGUS) and spending a lot of money on medication, veterinarians and horse owners should focus on preventing the condition using better management practices. This was a key message from Ben Sykes, BVMS, MS, MBA, Dipl. ACVIM, PhD, FHEA, a veterinarian and gastrointestinal disease researcher based in New South Wales, Australia, during his presentation at the 2024 National Alliance of Equine Practitioners Convention, held Sept. 25-28 in Saratoga, New York.

“Anytime we discuss EGUS it’s important to appreciate that squamous and glandular disease are two completely different diseases,” said Sykes. A horse may have only one type of ulcer, or if they’re particularly unlucky, they can have both simultaneously.” Squamous ulcers occur in the upper third of the stomach while glandular ulcers form in the lower region.

Sykes highlighted three factors that remain crucial when preventing squamous disease:

1. Roughage: amount and timing;
2. Nonstructural carbohydrates: amount per meal; and
3. Exercise: amount and timing.

Optimizing Feed for Ulcer Prevention in Horses

“We want a nice, firm ball made of long-stem roughage (floating in the stomach’s gastric fluid),” said Sykes. “And we want this ball to have structural integrity as well as strong buffering capacity. The simplest way to get that is to offer free-choice hay and, in some cases, to tweak how we offer the feed to optimize the grazing period. The aim is about 1.5% dry matter per day, which is about 2% body weight on an as-fed basis.”

Sykes noted that study results on the protective effect of pasture in horses with a history of squamous disease vary dramatically. He suggested this could be because of pasture type. For example, in one study researchers showed that horses with pasture access were three times less likely to have squamous disease than stabled horses, but that was a dry pasture. Authors of other studies have, counterintuitively, demonstrated no protective effect of pasture turnout, especially on fields with high levels of nonstructural carbohydrates (NSCs) and soft, watery grasses.

“We don’t give our horses at risk of ulcers sweet feed, and pasture can be like sweet feed in terms of NSCs,” said Sykes. “In the stomach, some pastures with high NSCs can make sugar soup that is not protective like a ball of roughage. It may, in fact, increase the risk of squamous ulcers due to the contributions of fermenting NSCs damaging the mucosa.”

In terms of feed timing, Sykes said offering alfalfa hay before exercising the horse is most beneficial. This optimizes the roughage ball for protection before the highest risk period for damage to the squamous mucosa (i.e., exercise).

Monitoring a Horse’s NSC Intake

While the amount of NSC a horse eats contributes to squamous disease, Sykes suggested it’s probably an overstated risk factor for most riding horses.

“The majority of riding horses eating modern, well-formulated diets don’t eat enough NSCs for it to be a major driver of disease,” said Sykes. “It’s usually only the super-high performance horses or those without well-formulated diets. For most horses we need to worry less about this and focus more on roughage.”

Still, horses should not consume more than 1 gram of NSC/kilogram (of body weight)/meal, and ideally you should aim to feed less than 0.5 g NSC/kg/meal.

Adding beet pulp to the diet might also be useful. “Feeding beet pulp reduced the risk of squamous ulcers fivefold in one study,” said Sykes. “This is a cheap and easy management change with apparent benefits.”

Reducing the Horse’s Exercise Duration

“During exercise, horses contract their abdominal muscles, effectively lifting the acid level onto the area of the squamous mucosa,” said Sykes. “It’s the durationof exercise at the trot or above, not intensity, that is the primary driver for squamous ulcer risk. As a recommendation, aim for an average of less than 30 to 40 minutes per day. That’s still quite a lot.”

As a solution, Sykes recommended a faster cooldown, noting that the sooner the horse slows to a walk, the sooner the acid in the stomach settles to its normal location.

Ideally, riders should not exercise their horses first thing in the morning when no ball of forage exists in the stomach to prevent stomach acid splashing. Instead, it’s preferable to exercise after the horse has spent some time grazing or eating hay to reinforce its roughage ball.

If you must exercise in the morning, do it after the horse has eaten a significant roughage-based meal.

“This meal should include hay, not short-stem substitutes like cubes and pellets,” said Sykes. “Cubes and pellets form soup, not a roughage ball, and soup doesn’t stop acid from splashing around. Horses also chew two to three times less when eating cubes and pellets than when eating hay. Less chewing equals less saliva, leading to less natural buffering. This, in effect, gives a double negative of less buffering and no roughage ball, leaving acidic stomach contents free to splash around despite alfalfa’s modest direct buffering capacity.”

He added that alfalfa makes the ideal hay for horses with squamous ulcers, but grass hay serves as a sufficient alternative when alfalfa is unavailable.

Managing Horses That Have Glandular Disease

Sykes noted that the list of actionable steps for preventing glandular ulcers is much shorter, simply because researchers don’t know as much about this disease as squamous.

“It’s a stress-based disease, so our focus is on behavioral aspects of management,” he said. “Diet has not been shown to be a causative factor for glandular ulcers, but it might be a therapeutic target. Some studies have shown that glandular ulcers can be improved by reducing carbohydrates and including alfalfa hay. And there may also be some benefit in adding oils, specifically marine-derived omega-3s.”

Sykes said in his opinion, the No. 1 way to prevent glandular ulcers is to provide sufficient rest days. He recommended scheduling two to three days of rest per week and removing confounding stressors such as orthopedic disease, poor saddle fit, and other causes of chronic pain.

“If glandular disease is a disease of stress, then it makes sense that other causes of pain can contribute to glandular disease,” Sykes said.

Additional research-supported ways of preventing glandular disease include minimizing handlers and trainers, offering a regular routine, massaging or grooming the horse, and playing relaxing music.

“Enriching the horse’s environment should help prevent glandular ulcers,” said Sykes. “Every horse needs a friend to groom and cuddle, and the worst thing we’ve done for horses is take a herd animal and make it live in isolation. Some European countries are legislating that horses must have an equid companion, which is a great step forward.”

Take-Home Message

“By focusing on these items, we theoretically should be able to manage squamous ulcers out of most riding horse populations,” said Sykes.

He did point out to practitioners that it’s hard to offer everything to every owner. “To be successful, we need to pick what each owner can do, but we can make an important difference with relatively simple interventions.”