How to Help Prevent Gastric Ulcers in Horses

Gastric ulcers are a common concern in horses, particularly those in regular work, travelling frequently, competing, undergoing changes in routine or spending long periods without forage. While some horses appear outwardly healthy, others may show subtle signs such as reduced appetite, sensitivity around the girth, changes in behaviour, poor performance, weight loss, recurrent mild colic or reluctance to move forward under saddle.

These signs are not specific to ulcers, however, and a veterinary examination is essential. Gastroscopy remains the most reliable way to confirm gastric ulceration and determine which part of the stomach is affected. Horses can develop disease in the upper squamous region, known as Equine Squamous Gastric Disease, or the lower glandular region, known as Equine Glandular Gastric Disease. These conditions have different risk factors and may require different treatment approaches. 

Medication prescribed by a veterinarian may be necessary to heal existing ulcers. Feeding and management changes are then vital for reducing ongoing irritation and lowering the risk of recurrence.

Keep Forage Available

One of the most important ways to support gastric health is to avoid leaving the horse with an empty stomach for extended periods.

Unlike people, horses continuously produce stomach acid, whether they are eating or not. When a horse chews forage, saliva is produced, helping to buffer stomach acid. The forage itself also creates a fibrous mat within the stomach that can reduce acid splashing onto the sensitive upper lining, particularly during exercise.

Where practical, horses should have frequent or near-continuous access to suitable pasture or hay. Slow-feed hay nets can help extend eating time for horses that consume their forage quickly. Horses that require restricted calorie intake still need sufficient fibre, so owners may need to use lower-energy hay, soaked hay or appropriately designed slow feeders rather than simply reducing forage to very small meals.

Lower forage intake, fewer daily meals and prolonged periods without food have all been associated with increased risk of squamous gastric disease. Access to pasture and turnout with other horses may also reduce risk in some horses. 

Feed Before Exercise

Exercising on an empty stomach can increase acid exposure in the upper part of the stomach. Providing a small forage meal before work may help create a protective fibre mat and encourage saliva production.

Lucerne is often recommended before exercise because its protein and calcium content provide greater buffering capacity than many grass hays. Research has associated lucerne feeding with higher gastric pH and reduced severity of squamous ulceration in some horses. 

A small amount of lucerne chaff or hay approximately 20 to 30 minutes before work may therefore be useful for an ulcer-prone horse, provided lucerne is suitable for the horse’s overall diet.

Limit Large High-Starch Meals

Large meals of cereal grains can increase the risk of gastric irritation. Starch that is rapidly fermented in the stomach produces volatile fatty acids, which may damage the squamous lining when combined with an acidic environment.

Where additional calories are needed, consider feeds based primarily on digestible fibre and fat rather than relying heavily on cereal grain. Suitable options may include:

• Unmolassed beet pulp, including products such as Speedi-Beet

• Soy hulls

• Lupins

• Lucerne

• Stabilised rice bran

• Low-starch complete feeds

• Appropriate vegetable or linseed oils

Unmolassed beet pulp is a highly digestible fibre source that is naturally low in starch. Lupins also generally contain much less starch than cereal grains and can provide useful protein and energy. Neither ingredient should automatically be considered an ulcer-causing feed. Their suitability depends on the complete ration, serving size, processing, sugar and starch content, and the individual horse.

If concentrates are required, divide them into several smaller meals rather than feeding one or two large meals. Veterinary guidance commonly recommends reducing starch intake and using low-starch feeds as part of ulcer management. 

Support the Entire Digestive System

Gastric health should not be considered in isolation. A horse’s stomach, small intestine and hindgut all depend on a consistent supply of fibre, water and appropriately balanced nutrients.

Sudden diet changes can disrupt the microbial population within the hindgut, potentially contributing to loose manure, gas, discomfort and poor feed utilisation. Introduce new feeds gradually over at least seven to fourteen days, with longer transitions for sensitive horses.

Ensure clean water is always available and provide adequate salt to encourage normal drinking. Dental care is also important because horses with sharp teeth or poor chewing ability may not process forage properly.

Supplements That May Support Digestive Health

Digestive supplements can be useful additions to a well-designed management and feeding program, but they should not be expected to cure diagnosed ulcers.

Pectin and lecithin

Pectin-lecithin combinations are commonly included in gastric-support products. They are intended to support the protective mucous barrier and help coat the stomach lining. Research results have been variable, so these products are best viewed as supportive rather than replacements for veterinary treatment.

Buffering minerals

Calcium, magnesium and other buffering ingredients may temporarily help neutralise acidity. Lucerne naturally supplies calcium and protein and has demonstrated buffering effects. Commercial antacid ingredients may provide only short-term effects because horses continue producing acid throughout the day.

Live yeast and probiotics

Live yeast products, including strains of Saccharomyces cerevisiae, are generally used to support fibre digestion and a stable hindgut environment. Probiotics may also support intestinal microbial balance, although effectiveness can vary significantly between products and strains. These supplements are more relevant to overall digestive and hindgut health than to directly healing stomach ulcers.

Prebiotics

Prebiotic ingredients such as mannan-oligosaccharides, fructo-oligosaccharides and inulin provide substrates for selected beneficial gut microbes. They may support microbial stability but should be introduced carefully, particularly in horses with sensitive digestive systems.

Omega-3 fatty acids

Marine-derived omega-3 fatty acids containing DHA and EPA, along with linseed-based sources of alpha-linolenic acid, may support healthy inflammatory responses and general digestive health. Evidence for directly preventing or treating equine gastric ulcers remains limited, so they should not be marketed as ulcer treatments.

Herbal ingredients

Slippery elm, marshmallow root, aloe vera and liquorice are often found in digestive supplements. While these ingredients are traditionally used to soothe the digestive tract, the quality of equine research is mixed or limited. Herbal products may also interact with medications or competition rules, so professional advice is recommended.

Reduce Stress Where Possible

Ulcer prevention involves more than feed. Stall confinement, transport, intense training, competition, weaning, social isolation and frequent changes in routine may all contribute to stress.

Provide regular turnout, companionship, predictable feeding times and adequate rest between demanding training or travel periods. Horses that become anxious when stabled may benefit from more visual contact with other horses, increased forage availability and environmental enrichment.

Exercise itself is not harmful, but repeated high-intensity work can increase pressure within the abdomen and push acidic stomach contents toward the vulnerable squamous lining. Feeding forage before exercise and avoiding unnecessary fasting may help reduce this exposure.

Work With Your Veterinarian and Nutrition Professional

Changes in appetite, behaviour or performance should never automatically be blamed on ulcers. Dental pain, musculoskeletal problems, hindgut disturbances and other medical conditions can cause similar signs.

Where ulcers are suspected, speak with your veterinarian before relying on supplements. Prescription omeprazole remains the primary treatment for many cases of gastric ulceration, although glandular disease may require a different or combined treatment plan. 

The most effective long-term approach combines veterinary treatment when required with abundant forage, smaller low-starch meals, suitable turnout, stress reduction and a carefully balanced diet. Supplements may provide additional support, but the foundation of digestive health will always be good feeding and management.