Question: Are some horses more likely to develop gastric ulcers than others? I have three middle-aged geldings that I keep on my own farm. They are managed almost identically, with plenty of hay and turnout and only enough grain to keep their condition up. They are all trailered off the property occasionally to shows and events, but I don’t think their lives are particularly stressful. Two of my horses have no gastrointestinal problems, but the third seems to have chronic ulcers. He was diagnosed about a year ago after a minor bout of colic. Omeprazole helped but he became uncomfortable again just a few weeks after the treatment stopped. He was treated again and, once again, it helped for only a short time. Is there anything else I can try? I can’t afford to ship him to a clinic for an endoscopy.

Answer: Several factors can affect an individual’s susceptibility to ulcers. For squamous disease (ulcers occurring in the top third of the stomach), eating behavior often plays a role. Factors include how much roughage, like hay, a horse eats each day and when they eat it. Horses that go a long time between meals—for example, “fasting” between the evening feeding and morning breakfast—are at higher risk of squamous ulcers because the upper stomach lining is exposed to gastric acid during that period.

Squamous ulcers: Preventive measures

To reduce the likelihood of squamous ulcers, you can try using slow feeder hay nets overnight. These extend the time it takes for horses to eat their hay, reducing the overnight fasting period and thus helping protect the stomach lining from excessive acid exposure. Additionally, exercising horses in the afternoon after they have eaten roughage throughout the day is beneficial. Feeding the horse alfalfa hay before exercise is better than other options like chaff or pellets, because this forage requires more chewing, which stimulates a greater production of saliva that helps buffer the stomach. Hay is also more effective at forming a protective ball of roughage in the stomach, compared with chaff or pellets, which prevents acid from splashing around.

In contrast to squamous disease, glandular ulcers (lesions affecting the lower two-thirds of the stomach) have a clear breed association; for example, Warmbloods are more prone to glandular ulcers. In addition, some individuals seem to be more susceptible to this condition for reasons that are not yet understood.

Glandular ulcers: Preventive measures

Glandular ulcers are more challenging to address with management. That said, there are things you can do to reduce your horse’s risk. One is to ensure that they get two to three rest days per week. Another is to reduce environmental stressors. Certain types of music might be helpful in soothing a horse’s anxiety, and massage may also be beneficial.

If management alone isn’t enough to prevent ulcers, specific feed supplements may help. But it’s crucial to choose a product that has been proven effective through published, peer-reviewed evidence and has been studied for the
specific type (squamous and/or glan-dular) of ulcers.

Ben Sykes BVMS, Dip. ACVIM, PhD

Southern Cross University

Lismore, NSW, Australia

Our Expert: Ben Sykes BSc BVMS MSc MBA Dip. ACVIM PhD FHEA, is a professor at Southern Cross University in Lismore, Australia. A practicing veterinarian for more than 25 years, Sykes is board certified with the College of Veterinary Internal Medicine in large animal internal medicine. Sykes has a strong interest in clinical research, with a focus on equine gastrointestinal diseases.