Gastric Ulcers

Maximising Digestive Health: Equine Gastric Ulcer Syndrome (EGUS)

Chestnut horse looking at flankWhilst a horse may be large, its digestive system is delicate and digestive health is vital for the overall health of the horse (Geor, 2005). Having evolved to graze for up to 16 hours a day, this delicate system adapted to consume a high fibre, low starch diet. Whilst high levels of exercise may mean that forage alone may no longer meet the horse’s energy requirements, modern feed and management practices can compromise digestive health.

Understanding EGUS
The term Equine Gastric Ulcer Syndrome includes ulcers in both the glandular (lower) and nonglandular (upper) regions of the stomach, as well as the oesophagus and upper duodenum (Andrews et al 1999). It has been estimated that approximately 80-90% of racehorse in training (Murray et al 1996)) and approximately 50% of competition horses and leisure horses may have nonglandular ulcers (reference, Luthersson et al 2009). Whilst glandular ulcers are probably the result of a breakdown in the mucosal defence mechanisms of the stomach lining, nonglandular ulcers are thought to be largely caused exposure to hydrochloric acid (Andrews et al 2017).


  • How diet may increase the risk of non-glandular ulcers
      • Reduced forage intake
        Access to ad lib forage promotes increase saliva production, thus providing a natural buffer for stomach, whilst fasting has been seen to reduce stomach pH compared to horses fed ad lib hay (Murray and Schusser 1993). More recently, Pedersen et al (2015) reported feeding forage once per day increased the risk of ulcers compared to horses fed forage at least twice per day. Furthermore, feeding forage and short chopped fibre helps to produce a ‘fibre mat’ on top of the contents of the stomach, thus helping to prevent ‘gastric splashing’ during exercise.
      • High starch intakes:
        High levels of starch entering the stomach as result of feeding large cereal based meals results in an increase of lactic acid and other volatile acids which in turn lowers pH. In one study, the risk of nonglandular ulcers (grade 2 or higher out of 5) was found to be 2.4 times higher in horses consuming more than 1g of starch per kilogram of bodyweight per meal (Luthersson 2009).
  • How you can help
      • Feed ad lib forage where ever possible. A minimum daily intake of 15g per kilogram of bodyweight (1.5% bodyweight) dry matter per day is recommended for all horses, including those in heavy exercise.
      • Divide restricted forage rations into as many smaller servings as possible to avoid long periods without forage. Allowing access to forage or short chopped fibre prior to exercise may also help to prevent gastric splashing.
      • Choose feeds based on short chopped fibre to help to extend eating time. Including some alfalfa may be helpful as the high levels of protein and calcium may provide a natural acid buffer.
      • Feed less than 1g of starch per kilogram of bodyweight per meal and ideally less than 2g per kilogram bodyweight per day.
      • Avoid using electrolytes pastes. Holbrook et al (2005) reported an increase in the number and severity of ulcers in endurance horses given electrolytes via syringe.
      • Provide water at all times. A lack of water in horses out at grass has been shown to increase the risk of non-glandular ulcers (Luthersson et al 2009).
  • The BETA EGUS approval mark

    WINERGY Equilibrium Growth was one of the first feeds to be awarded the BETA EGUS approval mark which identifies feeds as being suitable for horses and ponies prone to gastric ulcers when fed as part of a balanced diet. In order to be awarded this mark, feeds must pass a rigorous 3 stage approval process which includes independent nutrient analysis.

  • References
    • Andrews, F. M., Bernard, W., Byars, D., Cohen, N., Divers, T., MacAllister, C., McGladdery, A., Merritt, A., Murray, M., Orsini, J., Vasistas, N., 199a. Recommendations for the diagnosis and treatment of equine gastric ulcer syndrome (EGUS). Equine Veterinary Education 11, 262-272.
    • Andrews, F. M., Larson, C., Harris, P., 2017. Nutritional management of gastric ulceration. Equine Veterinary Education 29 (1), 44-55.
    • Geor, R.J. (2004) Nutritional management of the equine athlete. In: Equine Sports Medicine and Surgery. Eds Hinchcliff, K.W., Kaneps, A., and Geor, R.J. Saunders USA , pp 815-835.
    • Holbrook, T. C., Simmons, R. D., Payton, M. E., MacAllister, C. G. (2005). Effect of repeated oral administration of hypertonic electrolyte solution on equine gastric mucosa. Equine Veterinary Journal 37, 501-504.
    • Luthersson, N., Hou Nielsen, K., Harris, P., Parkin, T. D. N., 2009. Risk factors associated with equine gastric ulceration syndrome in 201 horses in Denmark. Equine Veterinary Journal 41, 625-630.
    • Murray, M. J. and Eichorn, E. S., 1999. Effects of intermittent feed and deprivation, intermittent feed deprivation with Ranitidine, and stall confinement with free access to hay on gastric ulceration in horses. American Journal Veterinary Research 57, 1599-1603.
    • Murray, M. J. and Schusser, G. F., 1993. Measurement of 24-h gastric Ph using an indwelling ph electrode in horses unfed, fed, and treated with ranitidine. Equine Veterinary Journal 25, 417-421
    • Pedersen, S., Windeyer, C., Read, E., French, D., Cribb, A., Macload, H., Base. H., 2015. Prevelance of and risk factors for gastric ulceration in showjumping warmbloods. Journal Veterinary Internal Medicine 29, 1239-1240.