Causes of Ulcers in the Horse
Marty Adams, PhD, PAS - Equine Nutritionist for Southern States
Ulcers are a common problem in horses with those especially in strenuous activities. These occur when the stomach or intestinal lining is damaged and the underlying tissue is exposed. Ulcers cause blood loss and anemia with many negative effects on their health and performance. Gastric ulcers occur in the lower esophagus, stomach and upper small intestine. Colonic ulcers appear in the large intestine, resulting in loss of serous fluid with hypoproteinemia (protein loss) and chronic diarrhea as symptoms.
There are multiple factors causing ulcers in the horse, including:
- Amount of Exercise - The most common way this can occur is thought to be the splashing effect of the acidic gastric contents onto the upper, nonglandular portion of the horse’s stomach lining. The splashing effect of acidic gastric contents onto the upper stomach region (occurs whenever the horse moves from a walk to a faster gait (trot, pace, canter or gallop). The nonglandular region of the stomach has no protective mucus coating compared to the lower, glandular stomach of the horse. This effect explains the higher occurrence of gastric ulcers observed in race horses, due to the prolonged splashing effect of a fast, prolonged gait. Stress may decrease blood flow to the stomach and increase stomach acid production due to increased gastrin secretion. Gastrin is a hormone that increases gastric acid secretion, which can result in more frequent and severe gastric ulcers.
- Medications - The use of non-steroidal medications (Phenylbutazone, Banamine and corticosteroids) have side-effects of decreasing gastric and intestinal mucus secretion and increasing gastric acid secretion. Their use increases the occurrence of gastric and colonic ulcers.
- Fasting – These are times when the horse’s stomach is empty and susceptible to damage. Horses evolved as grazers, eating many small meals frequently, while hydrochloric acid is continually secreted in the stomach. The stomach is rarely empty in a grazing horse and stomach acid can be neutralized by dilution. With modern horse management, many horses are fed large meals only twice-daily with limited access to pasture grazing. These fasting periods allow for increased acid concentration in the stomach and greater ulcer risk.
- Feed Type - The type and amount of hay or roughage has a role in ulcer development. Roughage requires more chewing than grain and pelleted feeds, stimulating the increase of saliva. Saliva contains bicarbonate, which reduces gastric acidity and ulcer occurrence on high roughage compared to high grain diets. The rate of gastric ulcers in horses on alfalfa hay is less than horses fed grass hay.
Legends® GastroTech™ Supplement has been found to be effective in significantly improving gastric health in actively exercised horses.