by: Nancy S. Loving, DVM
November 01 2008, Article # 10647
For more than a decade equine gastric ulcer syndrome (EGUS) and colonic ulcers have been linked to performance and health problems in horses. Today research continues to improve our understanding of ulcers, and the results are beginning to help veterinarians develop new strategies for prevention and treatment.
Ulcers In Three Days
Recent studies have shown that within just three days of a stress condition, a horse can develop gastric ulcers. Frank Andrews, DVM, MS, Dipl. ACVIM, formerly of the University of Tennessee and now the director of the Equine Health Studies Program at Louisiana State University's School of Veterinary Medicine, has been at the forefront of gastric ulcer research.
"For gastric ulcers to develop there needs to be exposure to hydrochloric acid (digestive juices of the stomach) and to volatile fatty acids (VFAs) and organic and bile acids," says Andrews. (VFAs are fermentation byproducts of sugar sources found in hay or grain, while bile acids reflux from the small intestine.) "With just three to four hours of exposure to these substances, tissue resistance dramatically decreases. If acid exposure continues, tissue begins to slough away, with severe damage within 12 hours."
Scott McClure, DVM, PhD, Dipl. ACVS, assistant professor in the Department of Veterinary Clinical Sciences at Iowa State University, examined the impact of stress conditions on development of ulcers. His study reproduced conditions involved with attending a horse show--the horses were hauled for four hours, stabled in a box stall for three days, exercised on a longe line twice daily, then transported home.
"On Day 5 we could already see reddening and thickening of the stomach lining," says McClure. "Seven of 10 horses had some ulcers, although not large ones. If you maintained the stress, you would likely see some early clinical signs, like decreased feed intake and general 'uncomfortableness' of the affected horses."
McClure notes that changes to the stomach lining are visible via endoscopic exam by Days 5 or 6, whereas clinical signs don't generally appear until Days 7-10. Small ulcers that are visible at Day 5 show significant ulceration by Day 8.