Veterinarians Discuss Gastric Ulcer Treatment Strategies for Horses
Equine gastric ulcer syndrome is a prevalent and painful disease affecting horses’ stomach lining. It can also be challenging and expensive for horse owners and veterinarians to manage.

At the 2019 Annual American Association of Equine Practitioners Convention, held Dec. 7-11 in Denver, veterinary attendees gathered for a table topic discussion about treating gastric ulcers. Frank M. Andrews, DVM, MS, Dipl. ACVIM (LAIM), LVMA Equine Committee professor and director of the Equine Health Studies Program and section chief of large animal medicine at Louisiana State University, and Sarah Reuss, VMD, Dipl. ACVIM, equine professional services veterinarian with Boehringer Ingelheim, moderated the talk.

Gastric ulcers develop when portions of the horse’s sensitive stomach lining get exposed to stomach acid. Ulcers that form on the stomach’s upper mucosa cause equine squamous gastric disease (ESGD), and those that form on the lower glandular region cause equine glandular gastric disease (EGGD)—two similar conditions with different risk factors and management strategies. Glandular disease also tends to be more challenging to treat than squamous disease, said the moderators.

The only way to definitively diagnose either condition is with gastroscopy (passing an endoscope through the nostril and down the esophagus to view the horse’s stomach).

Veterinarians’ treatment of choice for ESGD is omeprazole. “My first line of treatment for EGGD is omeprazole plus sucralfate,” said Reuss. “If that’s not working, I may try misoprostol.”

She generally does not recommend administering all three drugs at once because A) You wouldn’t know which one worked, and B) Giving them in conjunction can impact their efficacy if not timed just right.

The moderators then discussed a variety of other therapies and management strategies.

Injectable Omeprazole

The current FDA-approved form of omeprazole (trade name GastroGard) is administered orally. A team in Australia, however, has developed a long-acting injectable form with promising results.

The once-a-week injection has a slow delivery and bypasses the stomach, Andrews explained, improving its bioavailability (absorption rate) over the oral form. The researchers studying this drug (Sykes et al.) have seen improved healing of both squamous and glandular ulcers. The licensed product, however, is only available in the U.K. and Australia, said Andrews.

Withholding Feed

In recent years researchers have determined that treatment might be more effective if owners withhold hay and feed from horses overnight, then administer omeprazole in the morning. Table topic attendees, however, questioned whether this is truly necessary.

“Hundreds of thousands of horses have been treated without doing this and have done just fine,” said Reuss. “It’s not a rule but, if practical, give the horse a slow feeder at night, GastroGard in the morning, then wait an hour before feeding.

“For every average horse with Grade 2 squamous ulcers, I’m not going to make them revamp their schedule. But I will tell them they’ll get more bang for their buck if they do,” she added.

Nutraceuticals

A significant portion of the discussion then turned to dietary supplement options and their efficacy.

Sea buckthorn berry Andrews said he found that this liquid product made from highly antioxidant berries had no effect on squamous or glandular ulcers. A more concentrated form, however, did prevent glandular gastric ulcers from forming, but it’s not commercially available.

SmartGut Ultra This product contains sea buckthorn berries, pectin, lecithin, and aloe vera, among other ingredients. In a study he did, Andrews said ulcers did not recur in horses receiving SmartGut Ultra after stopping omeprazole treatment, whereas they did in controls. “We feel pretty comfortable using it to maintain stomach health but not as a treatment,” he said.

Purina Outlast This product is a slow-release antacid containing calcified seaweed. In a study of horses that travel extensively, Andrews said squamous ulcer scores did not increase while the horses were on Outlast, though they did in controls.

Corn oil While corn oil has been shown to reduce gastric acid output in some studies, Andrews said his team did not find that it prevented squamous ulcer formation in a large study. Raw or stabilized rice bran oil also had no effect on ulcer scores. “With that being said, corn oil is certainly something you can use,” he added, “and it’s cheap.”

“If you have horses that are actively working, supplements may help to maintain stomach health and keep ulcer scores low, but they’re not going to treat the disease,” Andrews said.

Low-Starch Diets

In one study out of the U.K., researchers compared ulcer recurrence in two groups of horses on omeprazole: one consuming a low-starch diet and one a normal diet. Reuss said the low-starch group experienced fewer recurring ulcers than those on normal diets, whose ulcers recurred within a month.

Take-Homes

Andrews’ take-home messages for attendees included:

  1. Omeprazole is still the mainstay treatment for gastric ulcers (both ESGD and EGGD) in horses.
  2. Equine glandular gastric disease usually requires multiple therapies, including omeprazole with sucralfate and/or misoprostol.
  3. Diet is important for preventing disease recurrence, especially ESGD; low-carbohydrate (sugar) approaches are useful.
  4. To maximize treatment effectiveness, give omeprazole first thing in the morning, followed by a hay meal 60 minutes later.
  5. Supplements might improve stomach health but are not efficacious in treating gastric ulcers.
  6. Other omeprazole formulations might become available in the future, which could improve treatment success.

While much of the session focused on gastric ulcer treatment and prevention, in closing Reuss emphasized the importance of getting an accurate diagnosis.

“Horses always need to be scoped to first provide an accurate diagnosis and then subsequently to monitor response to treatment,” she said. “Without seeing before and after pictures, we cannot possibly know what treatments are actually working.”