Ulcers in Horses: Digestive Supplements and Acid Rebound

Diagnosing gastric ulcers in horses and clearing them with omeprazole takes commitment, but the benefits of gastrointestinal well-being outweigh any outlay of time, money, or inconvenience. As horse owners wrap up an ulcer-healing protocol, they should be aware of one side effect of omeprazole therapy, a condition known as acid rebound.

Reported in both humans and horses, acid rebound occurs after treatment with proton-pump inhibitor drugs such as omeprazole. In the days after treatment, a surge in acid production may happen, causing a significant drop in gastric pH and leaving the horse vulnerable to formation of new ulcers and digestive discomfort.

Nutritionists and veterinarians often recommend feeding a digestive supplement in combination with anti-ulcer medications and continuing supplementation as long as the risk of ulcers persists.

“Antacid supplements offer protection by neutralizing the excess acid, but they do not affect the amount of acid produced, so there is no acid rebound effect and no impact on protein digestion,” said Catherine Whitehouse, M.S., a nutrition advisor with Kentucky Equine Research (KER). “Effective digestive supplements are those that can increase gastric pH for a significant period of time after feeding. In addition to antacids, supplements containing coating agents offer direct protection to the stomach lining against prolonged contact with acid.”

Proper management of horses prone to digestive upset is key in reducing development and recurrence of gastric ulcers.

“Management strategies include offering a diet that keeps gastric ulcers at bay, one composed of free-choice forage and low-starch feed with elevated fermentable fiber and fat; giving several small meals throughout the day; maximizing the amount of daily turnout; and minimizing physical and emotional stress,” said Kathleen Crandell, Ph.D., a longtime nutritionist with KER.

Certain feeds may help reduce the incidence of gastric ulcers. Alfalfa (lucerne) is well known for its buffering capacity, and feeding it just prior to work seems especially effective. Useful sources of fat include corn oil and stabilized rice bran, both of which are rich in omega-6 fatty acids.

The stomach is not the only organ in peril, as over half of horses with gastric ulcers also experience hindgut (cecum and colon) disturbances. Total digestive tract supplements are commercially available and designed to provide support and relief from the damaging effects of excess acid in the foregut and hindgut. KER developed two digestive supplements for optimal gastrointestinal health, EquiShure and RiteTrac (available in the U.S.). Check out a lineup of gastrointestinal supplements available in Australia.

EquiShure is a unique, time-released hindgut buffer designed to combat hindgut acidosis, the result of excessive fermentation due to high grain intakes, grazing lush pasture, and the stress of day-to-day training. RiteTrac contains EquiShure in addition to fast-acting antacids and coating agents, thereby providing foregut and hindgut support for best-case digestive health.

EquiShure and RiteTrac were designed for long-term daily use as preventive measures to help maintain optimal digestive health and function. The identification of high-risk periods, with appropriate, well-timed intervention, can be challenging for caregivers, as there are numerous triggers that cause ulcers to form quickly. Offering a daily complementary digestive supplement supplies a safeguard for horses in danger of developing ulcers and for those suffering from subtle, subclinical digestive disturbances such as inappetence, loose manure, and chronic, low-level colic.