We are a research and production company specializing in animal health products such as veterinary drugs, mixed feed additives, and pre mixed feed additives
language
Equine Gastric Ulcer Syndrome – The Hidden Epidemic of Athletic Horses
Release time:
2026-08-29
EGUS: High Prevalence and Economic Impact
Equine Gastric Ulcer Syndrome (EGUS) is one of the most common digestive system diseases in horses, significantly impacting health status, feeding costs, and breeding economics. Often described as an "occupational disease" of horses, EGUS can affect virtually all types of horses—racehorses, sport horses, broodmares, and even recreational horses—at various stages of their lives.
What Is Equine Gastric Ulcer Syndrome?
Equine gastric ulcer syndrome is an umbrella term used to describe erosions, ulcerations, and lesions in the terminal esophagus, nonglandular squamous and glandular regions of the stomach, and proximal duodenum. In simple terms, it is the erosion of the stomach's protective mucosal barrier by gastric acid, leading to tissue damage and ulcer formation.
The unique anatomy of the equine stomach is a primary reason for this vulnerability. The equine stomach holds approximately 12 liters, accounting for only 8% of the total digestive tract volume. It is divided into two distinct regions: the squamous (nonglandular) region—the upper third, lined with tissue similar to the esophagus, lacking protective secretions; and the glandular region—the lower portion containing glands that secrete hydrochloric acid and pepsin. Approximately 80% of gastric ulcer lesions are found in the squamous mucosa of the nonglandular region—because this area lacks protective mechanisms and is continuously exposed to gastric acid.
How Prevalent Is It?
Equine gastric ulcer syndrome is extremely common in horses—truly a "hidden epidemic":
- The prevalence of EGUS in racehorses in active training and racing is estimated to be at least 90%.
- In nonracing performance disciplines (such as show jumping, dressage, and endurance), prevalence ranges from 40% to 60%.
- The prevalence in neonatal foals is estimated at 25%–50%.
- The incidence in broodmares is approximately 70%.
- Studies show that gastric ulcer rates in racehorses can reach 93%–100%.
- In horses where owners reported conditions or behaviors commonly associated with ulcers, gastroscopy identified ulcers in up to 92% of cases.
- In a study of 190 horses, 83.2% of examined horses were found to have EGUS.
Etiology and Risk Factors
The pathogenesis of equine gastric ulcers involves an imbalance between gastric acid and mucosal protection. Modern management practices are the primary contributors—in the wild, horses spend most of their day grazing, and while gastric acid is continuously secreted, it is constantly buffered by saliva from chewing and the feed itself. However, under modern husbandry conditions, horses face multiple risk factors:
1.High-concentrate (grain), low-forage diets
2.Intermittent (bolus) feeding: prolonged fasting with continuous acid secretion and no food buffer
3.Environmental stress: stall confinement, transport stress, social isolation
4.Intensive training and competition
5.Long-term use of NSAIDs (such as phenylbutazone and flunixin)
During intense exercise, increased intra-abdominal pressure compresses the stomach, forcing acidic gastric contents upward ("acid splash") onto the nonglandular mucosa, causing acid erosion and damage.
Clinical Signs
The clinical signs of gastric ulcers in horses are often vague and nonspecific, and many affected horses may even be asymptomatic. This is why the disease is called a "hidden epidemic." Common manifestations include:
1.Poor performance: declining athletic performance, failure to meet training expectations
2.Reduced appetite: picky eating, decreased feed intake
3.Intermittent mild to moderate colic, especially after eating
4.Weight loss or difficulty maintaining weight
5.Poor hair coat quality: rough, dull appearance
6.Behavioral changes: nervousness, aggression, irritability
7.Girth aversion/resistance when being tacked up, back soreness
8.Bruxism (teeth grinding), ptyalism (excessive salivation)
A study of competitive dressage horses found that the most commonly reported clinical signs included girth aversion (78%), poor performance (33%), and weight loss (30%) .
How Is It Diagnosed?
Gastroscopy (endoscopic examination) is currently the only definitive diagnostic method. The veterinarian directly visualizes the inside of the stomach to determine the presence, location, number, and severity of ulcers. There is currently no reliable blood or fecal laboratory test available to diagnose EGUS. While presumptive diagnosis based on clinical signs and treatment response is not unacceptable, it may expose the horse to inappropriate treatment regimens, as the severity and location of ulcers remain unknown.
Economic Impact
The economic burden of equine gastric ulcers on the horse industry is substantial:
Gastric ulcers are the most common condition in horse insurance claims, ranking as the most frequent claim between 2020 and 2025.
Gastric ulcers rank as the second most expensive type of claim, with an average claim cost of £2,802, and 11% of cases exceeding £5,000 in veterinary fees.
In 2021 alone, SEIB Insurance handled over 100 claims for gastric ulcers, of which 44% cost over £3,000 and 17% reached the £5,000 claims limit.
Gastric ulcers account for 11% of all horse insurance claims and nearly two-thirds (63%) of colic and digestive disorder-related claims.
The high prevalence, nonspecific clinical signs, and negative impact on performance make EGUS a significant clinical and economic problem within the horse industry.
Conventional Treatment Options
Currently, the proton pump inhibitor omeprazole is the gold-standard treatment for equine gastric ulcers. Omeprazole oral paste is the only FDA-approved medication for EGUS. Clinical studies demonstrate exceptionally high efficacy—in one field trial, 99% of ulcers improved and 86.7% completely healed in the omeprazole-treated group. In another study, 65% of treated horses showed complete healing and 94% showed improvement.
The standard treatment protocol is: omeprazole 4 mg/kg body weight orally once daily for 28 consecutive days. For prevention of recurrence, maintenance doses of 2 mg/kg or 1 mg/kg daily may be used.
Latest updates
FOLLOW US
ENQUIRY NOW
* Note: Please be sure to fill in the information accurately, we will contact you as soon as possible