Equine Gastric Ulcer Syndrome: Welfare and Management
Equine Gastric Ulcer Syndrome
Equine gastric ulcer syndrome (EGUS) is one of the most prevalent welfare problems in performance horses, affecting an estimated 60-90% of racehorses in training and 37-59% of pleasure horses. Gastric pain significantly impairs quality of life, performance, and behaviour. Understanding EGUS pathophysiology, risk factors, and management is essential for horse welfare.
Anatomy and Pathophysiology
The equine stomach is divided into two regions by the margo plicatus: the squamous (non-glandular) region and the glandular region. These anatomical regions differ in their ulcer risk and management:
Equine Squamous Gastric Disease (ESGD): Ulcers in the squamous region result from acid exposure. Unlike the glandular region, the squamous mucosa lacks protective mucous layer, making it vulnerable to acidic stomach contents splashing up during exercise and low-forage periods. ESGD responds well to proton pump inhibitors.
Equine Glandular Gastric Disease (EGGD): Ulcers in the glandular region are less well understood but may involve disruption of mucosal protective mechanisms. EGGD is less predictably responsive to omeprazole alone and may require sucralfate or misoprostol.
Risk Factors
- Limited forage access: Horses evolved for near-continuous grazing producing saliva that buffers stomach acid. Periods without food (overnight, during transport) increase acid exposure of squamous mucosa
- High-concentrate diets: Starch fermentation produces volatile fatty acids that damage squamous mucosa
- Exercise intensity: Galloping causes stomach contents to slosh, increasing acid exposure of squamous mucosa
- NSAID use: NSAIDs impair glandular mucosal protection
- Stabling: Reduced movement and social interaction may increase stress and EGGD risk
- Transport and competition stress
Clinical Signs
EGUS signs vary from subtle to severe: poor appetite, weight loss and poor body condition, dull coat, recurrent mild colic (particularly post-feeding), sensitivity when girthing, reluctance to work, altered temperament, stereotypies, and reduced performance. Many horses have significant ulceration with minimal clinical signs, emphasising the importance of gastroscopy for diagnosis.
Diagnosis
Gastroscopy — passing an endoscope into the stomach — provides definitive diagnosis and grading (0-4 scale for squamous region; 0-2 for glandular region). It is the only way to accurately assess ulcer presence, severity, and distribution. Treatment response monitoring by repeat gastroscopy confirms healing.
Treatment
Omeprazole: The cornerstone of ESGD treatment (licensed as Gastroguard/Ulcerguard). Treatment doses of 4mg/kg daily for 4-8 weeks heal most squamous ulcers. Maintenance doses (1-2mg/kg) reduce recurrence risk.
Sucralfate: Provides mucosal protection; used alongside omeprazole for EGGD, particularly pyloric and glandular disease.
Management changes: Equally important as medication — increasing forage access, reducing concentrate feeding, providing hay before exercise, minimising fasting periods, and addressing stressors reduces recurrence.
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