Studies have shown that gastric squamous (the non-glandular area of the stomach) ulcers affect approximately 80-95% of racehorses, and more than half of the entire domestic horse population. A recent study from Murdoch University in Australia determined that omeprazole (a proton-pump blocker) is more effective than ranitidine (a histamine inhibitor) when treating gastic squamous ulcers in racehorses. The study was published in the Nov. 15, 2005, edition of the Journal of the American Veterinary Medical Association.

Gastric ulcers can induce pain and mild colic in horses, which can hinder their performance. Gastric squamous ulcers, the most common form of ulceration, cause a break or erosion in the stomach lining. Gastric ulcers occur in all ages and breeds of horses, but are most prevalent in foals and performance horses.

Clinical signs of gastric ulcers can include poor performance, weight loss, and mild colic. Risk factors thought to cause ulcers are feeding a high-concentrate diet, limited grazing and turnout, stall confinement, intense exercise, and stressful environments. Prolonged usage of non-steroidal analgesic medications such as Bute and Banamine can also cause ulcers in the acid-secreting glandular part of the stomach and contribute to squamous ulceration. Previous studies showed ulcers can be reduced by altering the horse’s environment to eliminate or reduce risk factors. This can be difficult or unfeasible in a training situation, which is why the use of anti-acids has become widespread.

The Murdoch study examined the effects of gastric ulcer medications omeprazole (such as GastroGard) and ranitidine (Zantac) in 60 racing Thoroughbreds prescreened to have gastric squamous ulcers