Gastric Ulcers

What are Gastric Ulcers or Equine Gastric Ulcer Syndrome (EGUS)?

Gastric ulcers or EGUS can be caused by prolonged exposure of the stomach lining (gastric mucosa) to gastric juices resulting in ulceration and sometimes bleeding. The horse’s stomach can broadly be divided into two sections; the upper non-glandular region where food enters the stomach, and the lower glandular region where hydrochloric acid is produced. Although the lower region is constantly exposed to acid, it generally has adequate protection and lesions are most commonly found in the upper region. Lesions in the lower region are unlikely to be diet related and may be more common in foals and older horses.

Get in touch with our expert nutritionists for more information on gastric ulcers in horses. 




  • Who is at risk?

    Horses and ponies at highest risk of gastric ulcers are those whose activities, routine and/ or inappropriate feeding practices make them more susceptible. Risk factors include:

    • Low fibre/ forage, high starch diets
    • Stress (including foals at weaning) 
    • Intensive training and prolonged transport
    • Some medications such as NSAIDs
    • General ill health

    It has been suggested that 80-90% of horses in training and 50% of competition horses have gastric ulcers; possibly due the combination of intense work, prolonged periods of stabling with little or no forage and increased stress levels. Saliva provides a natural buffer for stomach acid but is only produced when the horse chews. This coupled with the fact that gastric pH drops in horses that have not eaten for several hours means that those stabled for long periods on restricted rations of forage are at a higher risk of developing gastric ulcers.

    Exercise may increase gastric acid production but also increases pressure in the abdomen which results in gastric acid ‘splashing’ onto the upper region of the stomach. Feeding plenty of forage/ chopped fibre forms a protective 'fibre mat' on top of the stomach contents, thus helping to prevent ‘gastric splashing’. Stress is also thought to be a major risk factor as it decreases the stomach lining’s defence mechanisms

  • Foals

    It has been suggested that 50% of foals suffer from gastric ulcers. Foals have a developing stomach lining which is thinner than adult horses increasing their risk of ulceration. The amount of gastric acid secreted in a foal’s stomach often increases at a time when they are not eating enough forage to buffer it which can also leave them more prone to ulceration. Start by ensuring that new foals receive adequate amounts of colostrum, which contains an epidermal growth factor that enhances development of the gastric mucosa. Encourage creep feeding to help increase the foal’s appetite for forage before weaning and try to minimise stress by preventing illness, rough handling, un-necessary transport and weaning too early or suddenly.

  • What to look out for?

    If you suspect your horse may have ulcers seek advice from your vet, as medication to reduce acid production and allow the ulcers time heal may be required initially. Not all horses will show obvious outward signs so look for subtle changes in temperament and discuss any of the following signs with your vet:

    • Irritability – this may just be when grooming, girthing-up or changing rugs
    • Loss of appetite
    • Poor body condition
    • Poor coat
    • Tucked up appearance
    • Teeth grinding
    • Crib-biting
    • Chronic diarrhoea (most common sign in foals)
    • Pot-bellied appearance
    • Poor performance
  • How nutrition plays a role

    Long term nutritional management plays a key role in helping to reduce the risk, frequency and severity of gastric ulcers. New research in collaboration with SPILLERS is the first to show that changes in the diet can help to manage gastric ulcers post omeprazole treatment. In this study, a change in diet (which included SPILLERS HDF Power Cubes) maintained the beneficial effects of omeprazole 6 weeks after treatment had stopped. In contrast, horses in the 'no diet change' group had regressed and at the end of the study, there was no significant difference between pre and post treatment gastric ulcer scores.

      • Base as much of the diet on forage as possible, maintaining a high fibre, controlled starch diet
      • A balancer is the ideal way to provide vitamins, minerals and quality protein for those able to maintain weight on forage alone
      • Research suggests that starch intake should be restricted to less than 1g per kilogram of bodyweight per meal and ideally less than 2g per kilogram of bodyweight per day. As a practical guide, choose high energy feeds containing less than 20% starch and low energy feeds containing less than 15% starch.
      • Feed small meals adding chopped fibre to help extend eating time. Try to include some alfalfa as the high protein and calcium content may help to buffer stomach acid
      • Oil can be added at up to 100mls per 100kg of bodyweight per day to provide additional energy (calories). However simply adding oil on top your horses current feed may unbalance the diet, so consider choosing a feed that already contains a higher level of oil
      • Add any additional oil gradually (approximately 100mls per week) and ensure the diet provides an additional 100iu of vitamin E for every 100mls of oil added – speak to a nutritionist for more advice.
      • Ensure water is available at all times
      • Avoid using electrolyte pastes, especially in those already prone to ulcers
      • Consider feeds awarded the BETA EGUS approval mark but remember these are not the only suitable options. 

    Research conducted in collaboration with SPILLERS has shown that diet can help to manage EGUS. Read our blog to find out more.

  • Forage Tips
    • Provide ad lib forage and daily turnout wherever possible
    • Do not restrict forage intake to less than 15g per kilogram bodyweight per day dry matter. In practice this equates to approximately 18g of hay or 20-24g of haylage per kilogram of bodyweight per day in horses and ponies without access to grazing - speak to a nutritionist for more advice.
    • Don’t leave horses for more than 6 hours without forage
    • Divide hay/ haylage between several double-netted, small-holed haylage nets to help extend eating time
    • Try to provide hay/ haylage whilst travelling
    • Allow access to forage or short chopped fibre before exercise to help maintain a fibre mat in the stomach
    • Do not use straw as the sole forage supply