Ulcers Shown to Affect Horses with No Risk Factors

While the rigors of training, showing, stall confinement, and travel have previously been shown to increase a horse's risk for gastric ulcers, a new study suggests that broodmares at pasture--with none of these risk factors--are likely to have ulcers as well.

The study, conducted by Sarah S. le Jeune, DVM, Dipl. ACVS, Dipl. ECVS, staff veterinarian at the University of California, Davis, revealed that 70.9% of the 62 Thoroughbred broodmares scoped had gastric ulcers. These mares had not been transported for at least two weeks prior to scoping, and all lived on the same farm under similar management.

"We know--or we thought--that pastured horses would have perfect mucosa," le Jeune said, noting the actual rate of horses affected by ulcers in this study is comparable to those in active race training.

While the overall ulcer rate in the broodmares was higher than expected, the mean grade of ulcer was 3.3 (on a scale of 1 to 5, one being least severe), which is considered mild. Only two mares had ulcers in the glandular region of the stomach (an area that is well-protected against acid damage) and these mares had poor body condition scores.

The researchers found no strong correlation between the prevalence of ulcers and any of their study parameters, which included age, pregnancy, race earnings, last race start date, size of herd, medical history (including use of non-steroidal anti-inflammatory drugs), number of live foals, number of years the mare was bred, and type of feed (whether alfalfa or grass hay).

Le Jeune said that one of the study hypotheses was that mares in a later stage of pregnancy would be more likely to have ulcers in the squamous portion (the non-glandular region of the horse's stomach, located in the inner one-third of the stomach and covered by "tender" tissue with minimal protection against acid injury) of their stomachs due to the intrabdominal pressure exerted by the foal pushing stomach acid into this portion. Researchers on the study discovered that this hypothesis was incorrect--mares scoped at a late stage of pregnancy and after foaling showed no change in stomach health.

One presentation attendee postulated that ulcers might be a natural condition for horses. Le Jeune said while that is a possibility, more research is needed to determine if the researchers' findings on this study are consistent with the ulcer rates on other farms.



Get research and health news from the American Association of Equine Practitioners 2006 Convention in The Horse's AAEP 2006 Wrap-Up sponsored by OCD Equine. Files are available as free PDF downloads.

About the Author

Erin Ryder

Erin Ryder is a former news editor of The Horse: Your Guide To Equine Health Care.

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