Gastric Ulcers in Polo Horses: Prevalence and Risk Factors

herd-of-polo-poniesResearchers know that gastric ulcers are common in horses competing in a variety of disciplines, such as endurance, racing, and show jumping. And recently, a Canadian research team added another discipline to that list: polo.

Heath MacLeod, a veterinary student at the University of Calgary Faculty of Veterinary Medicine, in Alberta, Canada, presented the study results in a poster presentation at the 2015 American College of Veterinary Internal Medicine Forum, held June 4-6 in Indianapolis, Indiana.

Ulcers can develop in both the squamous (top) and glandular (bottom) portions of a horse’s stomach. The lower glandular part of the stomach contains a mucosa with glands that secrete acid and pepsin, which aid in early food digestion. The glands also produce bicarbonate and mucus, which help form a protective barrier over the mucosal surface. This protects the glandular stomach from acid and pepsin’s damaging effects. The squamous region, however, has few defenses and is particularly susceptible to injury (i.e., ulcers) caused by stomach acid.

Many performance horses live in single stalls and are turned out and/or ridden alone or in small groups. Polo horses, on the other hand, often live and exercise in groups, MacLeod said.

“Therefore, ulcer occurrence and risk factors may differ in this performance discipline compared to previously studied populations,” he explained.

MacLeod and colleagues from the University of Calgary and TD Equine Veterinary Group, also in Calgary, examined 63 polo ponies from nine stables via gastroscopy. They also reviewed surveys completed by the horses’ grooms that included information such as feeding and housing practices, competition level (team polo play is handicapped on the basis of ability, and the players’ handicaps make up a team’s handicap; tournaments are held in three handicap categories: high-goal [20 goals or more], medium-goal [six to 14 goals], and low-goal [0 to four goals]), training protocol, and any medications administered.

MacLeod and colleagues determined that:

69% and 54% of horses examined had glandular and squamous ulcers, respectively;
Of those, 31% had glandular ulcers scored Grade 2 or higher (on a 0 to 4 scale ;the higher the grade, the more severe the ulcers), while 37% had squamous ulcers scored Grade 2 or higher;
For every polo game a horse participated in per month, his odds of squamous ulceration increased by 1.5 times; and
For every additional hour of exercise per week, a horse’s odds of developing any type of ulcer decreased slightly (11%).
“In this study, only exercise duration and numbers of games per month were associated with the presence of gastric ulcers,” MacLeod and colleagues concluded. “The increased risk of squamous observed with increasing numbers of games per month may be related to increased exposure of the squamous epithelium to gastric acid.”


Erica Larson, News Editor
Erica Larson, News Editor, holds a degree in journalism with an external specialty in equine science from Michigan State University in East Lansing. A Massachusetts native, she grew up in the saddle and has dabbled in a variety of disciplines including foxhunting, saddle seat, and mounted games. Currently, Erica competes in three-day eventing with her OTTB, Dorado, and enjoys photography in her spare time.

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