Equine veterinarians are well aware that gastric ulcers now fall into two distinct categories: squamous disease and glandular disease. When it comes to educating clients about how to feed their horses to prevent gastric ulcers, the diet and management details depend on the diagnosis.
“When I’m talking to horse owners, I am always encouraging them to please let your veterinarian scope your horse,” said Kelly R. Vineyard, MS, PhD, Senior Equine Nutritionist with Purina Animal Nutrition. “You really need to know what you’re dealing with, because that’s going to dictate some of our feeding and management strategies.”
She reviewed those strategies with veterinary professionals during the 2024 Purina Equine Veterinary Conference, in St. Louis, Missouri.
First, Recognize the Risk Factors
Vineyard said the three main risk factors for gastric ulcers are elevated exercise levels and intensity, inadequate forage, and soluble carbohydrate intake. “This is basically a description of a day in the life of the average performance horse,” she added.
So, when you walk into a barn, be cognizant of red flags such as a busy training environment, lots of activity, individual or minimal turnout, and large meals of high-starch feeds. Expect many of these horses to be candidates for gastric ulcers, and work with the owners to make diet and management changes that will keep their horses ulcer-free. Otherwise, even if you successfully treat the gastric ulcers, they’re likely to return.
Oral Omeprazole Best Practices
Upon diagnosing a horse based on endoscopy with squamous or glandular disease, most veterinarians prescribe omeprazole. Vineyard says she often gets asked whether horses should be fasted prior to omeprazole administration. She offers this general rule of thumb, based on data from a recent review paper: “Give omeprazole first thing in the morning (around 7 or 8 a.m.) after an overnight fast, wait 30 minutes, and if you’re also giving sucralfate, do it then, right before morning feed. Let the horse eat free-choice hay or pasture all day, give sucralfate again at the end of the day before their evening feed. And then pull the feed out and make sure they have enough hay to last until midnight.”1
To avoid rebound gastric hyperacidity in the 48 hours following the last dose of omeprazole, Vineyard recommended the following:
- Make sure the horse is receiving free-choice forage.
- Avoid transport and other stressful events.
- Avoid forced exercise.
These are simple steps you can encourage clients to follow for two days to help prevent the ulcers from coming right back.
Management Adjustments
Most management recommendations for horses with gastric ulcers focus on minimizing the risk of nonglandular/squamous disease, said Vineyard. These include:
- Don’t exercise the horse on an empty stomach; let them eat hay before riding.
- Create a calmer barn environment by reducing excessive traffic and noise.
- Increase turnout, if possible, preferably with one or two other horses.
- Maintain a routine feeding, grooming, and riding schedule.
- Use non-steroidal anti-inflammatories judiciously.
When it comes to managing glandular ulcers, more information has been coming out about the effects of exercise. “There is a direct correlation with the diagnosis of glandular ulcers and horses exercising five days or more per week,” said Vineyard. “So for the horses with glandular ulcers, at least two to three full days of rest a week is probably one of the best things you can do from a management perspective.”
Diet Adjustments
Diet changes go hand in hand with management recommendations. “Our guiding philosophy here is based on the mantra, ‘no acid, no ulcers.’ So we’re trying to manage gastric acidity, and there are lots of different ways we can do that though the diet,” Vineyard explained.
First and foremost, maximize pasture access. “There’s no better way to manage gastric acidity than with Dr. Green,” she said, acknowledging that prolonged turnout might not be an option for some barns and horses. In those scenarios, provide constant access to quality hay, utilizing slow feeders or small-hole haynets if concerned about calorie intake.
Don’t allow horses to fast for more than six hours—this is another reason to feed hay through slow feeders, said Vineyard.
“Feed smaller, more frequent meals (e.g., three meals a day instead of two large ones) of a high-fat/fiber, lower-soluble-carbohydrate concentrate,” she advised.
Incorporate alfalfa hay into the diet throughout the day. “To really get good buffering effects, they need it at regular intervals—1-2 pounds every five or six hours,” Vineyard said. “That’s going to maximize the positive effect of the alfalfa hay.”
Avoid giving paste electrolytes, which can be irritating to the gastric mucosa, and promote proper stomach pH by recommending a research-backed dietary supplement (e.g., Outlast Gastric Support).
In Summary
The diet and management strategies for gastric ulcer prevention are many, but they aren’t rocket-science. Veterinarians can learn to identify high-risk environments and provide their clients with practical, actionable steps they can take to keep their horses comfortable and ulcer-free.
1. Vokes J, Lovett A, Sykes B. Equine Gastric Ulcer Syndrome: An Update on Current Knowledge. Animals (Basel). 2023 Apr 5;13(7):1261. doi: 10.3390/ani13071261. PMID: 37048517; PMCID: PMC10093336.
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- Feeding Horses That Can’t or Won’t Eat
- Restricted Grazing Systems’ Effects on Equine Behavior and Welfare
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