Equine gastric ulcers: risks, symptoms and treatment

Gastric ulcers are not uncommon in horses. But as LARISSA BILSTON explains, there are strategies that can help to prevent and to heal them.

Gastric ulcers are quite common in horses of any age, with most studies estimating that between 50 to 90 per cent of horses have gastric ulceration. The highest prevalence occurs in racehorses (80-90%), and some studies indicate that over 60% of performance horses experience gastric ulcers at some point in their lives.

Equine gastric ulcers are typically categorised into two types based on the affected area: equine squamous gastric disease (ESGD), which impacts the upper, squamous part of the stomach; and equine glandular gastric disease (EGGD), which affects the lower, glandular region. Unfortunately, symptoms can be very vague and variable, with variation between individual horses and few links between symptoms and the type or location of the ulcerated tissue. In some cases, horses diagnosed with quite severe ulcers can present as symptom-free.

Since each disease has distinct causes, and different treatment protocols, successful management relies on accurate diagnosis via veterinary endoscopy.

Understanding ESGD

Horses evolved with a digestive tract designed for near continuous forage grazing, and any diet or management practice that strays from this can elevate the risk of ESGD. Ulcers in the squamous region of the stomach occur when the sensitive phospholipid lining in the upper stomach is damaged by acid exposure. The causes are multi-factorial, but common risk factors include:

• High-starch diets: Meals rich in grains and concentrates contribute to higher stomach acidity, which can damage the squamous lining. Meal fed horses often receive less forage which increases the risk.
• Long exercise durations: Intense or prolonged exercise increases the risk of acidic stomach contents splashing onto the squamous lining.
• Stabling: Horses kept off pasture, or restricted to stalls or small yards have limited access to forage, contributing to increased acid exposure and the likelihood of ulcers.
• Isolation: Lack of companion horses and herd living places a low level, ongoing stress on horses, creating another risk factor.

Symptoms

Squamous ulcer symptoms can resemble those of heartburn in humans. Watch for the following signs:

1. Poor performance: including altered stride length, fatigue and reduced aerobic capacity
2. Poor body condition or unexplained weight loss: Due to discomfort and reduced food absorption, horses with ulcers may struggle to maintain weight even with adequate food intake
3. Reduced appetite: Picky eating of hard feed and occasionally a reluctance to eat roughage.
4. Dull or rough appearance to coat
5. General discomfort, altered behaviour or colic: Horses might appear unsettled or show signs of discomfort during and after meals or exercise.

Prevention and treatment

Nutrition, medication and lifestyle are the pillars for successful ESGD treatment and management. The focus is on reducing stomach acidity and supporting stomach health through dietary modifications and supplementation. Lifestyle changes which encourage natural foraging and social behaviours are key for long-term success.

• Roughage focused diet: A high-roughage diet is crucial. Ideally, feed 1.5-2% of the horse’s body weight in roughage daily. Limit carbohydrates in favour of more forage-based foods. Avoid sugar and starch based hard feeds and treats. Eliminate cereals and their by-products from the diet, including grains, pellets and hay made from barley, wheat, rice, oats and corn. Choose feeds made from copra, super fibres (eg soy hulls) or oilseed meals such as soybean or lupin.
• Pre-ride feeding routine: Provide at least half a biscuit of lucerne hay immediately before riding. The hay forms a mat which soaks up free liquid and reduces acid splash into the higher regions of the stomach, helping to protect the squamous lining during exercise.
• Shorter rides: Research shows that limiting exercise duration with shorter, more frequent rides reduces acid splash. Minimising warm-up and cool-down times may also help.
• Omeprazole: Omeprazole, a proton pump inhibitor, is widely used for ulcer treatment. However, it requires continuous administration until ulcers are fully healed, often taking about 21 days for squamous ulcers. Long-term use of omeprazole is not advised due to its impact on calcium digestibility. Nutraceutical supplements may be beneficial after medication ends to alleviate rebound acid secretion effects.
• A balanced diet: This is essential for providing the nutrients necessary for gut healing. Oxidative stress is evident in horses with EGUS, increasing their need for antioxidants – so supplementation can be beneficial. Ask a qualified equine nutritionist to check the overall balance of your horse’s diet to ensure fibre, energy, protein, antioxidants, vitamins and mineral levels are adequate and in the correct ratios.
• Nutraceutical supplements: Although research on nutraceutical supplements has been limited, they may show promise in ulcer management. Some worth consideration as an aid to alleviating symptoms include: Omega-3 fatty acids (EPA, DHA and GLA); antioxidants (vitamins C and E, selenium, SOD); SB live yeast (Saccharomyces boulardii); pectin with lecithin; soy flour fermented with lactic acid bacteria delbrueckii lactis Rosell-187; and aloe vera, sea buckthorn and other herbs including licorice, marshmallow root, slippery elm, chamomile. Buffers are helpful for temporary relief before intense activity, but are not a long-term solution for ulcer healing.

Understanding EGGD

Glandular ulcers are primarily seen in performance horses, particularly in certain breeds, and often stem from stress, high workloads, or frequent handling changes. Major risk factors include:

1. Breed predisposition: Warmbloods are more prone to glandular ulcers
2. High work demands: Horses with limited rest days (more than five days of work per week) are at a higher risk
3. Multiple handlers: Having different riders or handlers may induce stress and behavioural changes
4. Stress from pain or physical discomfort: Physical or behavioural stressors can also contribute to ulcer formation
5. NSAIDS: The use of non-steroidal anti-inflammatory drugs such as bute.

Symptoms

Horses with glandular ulcers may exhibit different symptoms from those with squamous ulcers, although signs are not definitive. Look for:

• Pain and irritability: Discomfort and sensitivity around the stomach area may be apparent. This is often most noticeable as girthiness during saddling
• Reluctance to work: They may resist work, refuse to perform, or seem unenthusiastic about tasks they previously enjoyed
• Behavioural changes: They may display increased aggression or altered personality
• Colic episodes: While not as common as other symptoms, some horses with glandular ulcers may experience colic.

Treatment and management

Behavioural management is increasingly recognised as essential for preventing EGGD. Allowing horses adequate rest days, minimising handler changes, and encouraging social behaviours can reduce stress levels, which may play a significant role in EGGD development. Researchers are also studying the role of the gut microbiome in ulcer formation, although no direct bacterial cause has been found, differences in microbial populations may contribute to EGGD susceptibility. The treatment involves:

1. Focus on microbiome and diet: Studies suggest the importance of a healthy gut microbiome in preventing and managing glandular ulcers. While there is no evidence that Helicobacter bacteria affect horse ulcers, the microbial community in the glandular region in ulcer-affected horses is different to that in the healthy horse, indicating a possible link between microbiome health and ulcer risk. A forage-based diet with minimal sugar and starch hard feeds is therefore recommended. Diet recommendations for ESGD can be applied to horses with glandular ulcers as part of a well-balanced diet to help heal and maintain a healthy gut lining. Supplements tailored for stomach health help maintain balance in the gut microbiome and protect against stress-related flare-ups. They may be beneficial for horses with a predisposition to glandular disease.
2. Scheduled rest: Rest is essential for EGGD prevention and healing. Two to three rest days per week helps reduce stress and prevents strain on the glandular region of the stomach.
3. Social interaction: Providing companion horses and encouraging natural social behaviours can reduce stress levels and improve overall health. Reducing the number of human handlers to one to two people per horse also improves horse well-being and reduces EGGD risk.
4. Omeprazole: Omeprazole should be given after an overnight fast, followed by feeding one hour later. This regimen is more effective in targeting glandular ulcers. Healing often requires 4-6 weeks of consistent treatment due to the resilient nature of glandular ulcers.

Key takeaways

Follow these guidelines to support your horse’s digestive health, improve their comfort and performance, and reduce the likelihood of gastric ulcers developing or recurring.

• Prioritise roughage and fibre.
• Manage exercise and stress.
• Supplement wisely.
• Follow medication guidelines.
• Encourage socialisation and minimise handlers.

Managing equine gastric ulcers requires a multi-faceted approach combining diet, exercise moderation, stress reduction, and targeted treatments that rely on accurate diagnosis. Recognising risk factors early can help horse owners make adjustments that may prevent ulcer development.

Larissa Bilston, BAgrSc (Hons) is the Equine Nutritionist for Farmalogic.