Equine Gastric Ulcer Syndrome (EGUS)

“You can feed horses the best feed and train them with the best techniques, but if you don’t treat gastric ulcers they are unable to perform to the best of their ability.”

– Dr. Emily Sandler, International Dressage, Eventing and Showjumping FEI Veterinarian


The term EGUS was first used almost twenty years ago to describe gastric ulceration in the horse. We now understand that this is truly an umbrella term that encompasses primary and secondary erosive and ulcerative diseases of both the squamous and glandular parts of the stomach, even though the etiologies are not identical. A variety of clinical signs are associated with EGUS including poor appetite, poor condition, colic, and behavioural issues.  The expression of clinical signs does not necessarily correlate with the grade of lesion severity. Additionally, we have come to understand that EGUS may also result in poor performance. 3

3Sykes, B., Hewetson, M., Hepburn, R., Luthersson, N., & Tamzali, Y. (2015). European College of Equine Internal Medicine Consensus Statement—Equine Gastric Ulcer Syndrome in Adult Horses. Journal of Veterinary Internal Medicine, 29(5), 1288-1299.

horse stomach ulcers
The Disease Process of EGUS
Horses trained in urban areas were 3.9x more likely to have gastric ulcers2
When horses change lifestyles, it significantly increases their likelihood of developing EGUS1
Intermittent access to water increases the risk of EGUS as it has been shown that horses without access to water in their paddock are more likely to have ulcers than horses with constant access to water2
Symptoms of gastric ulcers can include: decreased performance, attitude changes to training, poor body condition, weight loss, poor appetite, poor hair coat, loose feces, low-grade colic and excessive time lying down
The only way to diagnose gastric ulcers is gastroscopy
Limiting stressful situations and reducing the amount of grain and concentrates in the diet aid in prevention

Risk Factors for EGUS2,4

Urban farm location
Lack of direct contact with other horses
Lack of access to hay or roughage
Lack of continuous access to water
   Trailering/ Hauling
Herd dynamics
Change in lifestyle

Clinical Signs

Poor appetite
Abdominal Pain (Colic)
Teeth Grinding
Attitude changes
Decreased performance
Reluctance to train
Poor body condition
Poor hair coat
Weight loss

90% of racehorses, 60-80% of competition horses, and 50% of pleasure horses suffer from gastric ulcers

If you are concerned that your horse may be suffering from EGUS or want to learn more ways to prevent it please talk to your veterinarian.
1 J Vet Intern Med 2015;29:1288–1299
European College of Equine Internal Medicine Consensus Statement— Equine Gastric Ulcer Syndrome in Adult Horses B.W. Sykes, M. Hewetson, R.J. Hepburn, N. Luthersson, and Y. Tamzali1

2 24. Luthersson N, Nielsen KH, Harris P, Parkin TDH. Risk
factors associated with equine gastric ulceration syndrome (EGUS)
in 201 horses in Denmark. Equine Vet J 2009;41:625–630.

4Effects of intermittent feed deprivation, intermittent feed deprivation with ranitidine administration, and stall confinement with ad libitum access to hay on gastric ulceration in horses
Murray MJ, Eichorn ES
Am J Vet Res, 1996.