Gastric Ulcer Prevalence at a Large Equine Center in China

Gastric ulcers in horses may be more prevalent than once thought. Gastroscopic examinations that directly visualized the stomach lining in 395 horses residing at a single equestrian center in China revealed a concerningly high rate of gastric ulcers.

Ulcers can occur in the squamous (upper), glandular (lower), or both regions of the stomach concurrently. While many clinical signs are attributed to gastric ulcers, such as rough coats, abdominal discomfort, decreased appetite, and teeth grinding, equine gastric ulcer syndrome (EGUS) can only be definitively diagnosed by gastroscopy.

“Some horses with gastric ulcers may show obvious signs of pain, but other consequences of gastric ulcers may be more subtle, such as poor performance, change in behavior, and weight loss. From a horse welfare and comfort standpoint, these are all situations we would like to avoid,” explained Ashley Fowler, Ph.D., a Kentucky Equine Research nutritionist.

Given the importance of EGUS and the need to find ways to prevent this disease, a group of Chinese veterinarians conducted a study to determine the prevalence of gastric ulcers in a large group of horses.^* In total, they performed gastroscopies on 395 castrated male horses residing at the Jaingsu Provincial Equestrian Club and participating in a variety of activities. A simple scoring system ranging from 0 (no gastric ulcers) to 4 (more than 10 ulcers or the presence of diffuse and large ulcers) was used to grade ulcers, which included both squamous and glandular lesions.

“Over three-quarters (78%) of the horses were diagnosed with EGUS, most of which were grade 1 or 2, meaning they had between 1 and 5 distinct ulcers. Further, most of the horses with EGUS did not show any clinical signs of disease,” Fowler said.

Delving deeper into the data, the researchers found that 90 horses had glandular ulcers only, which was more than the number of horses with squamous ulcers only (76). Significantly more horses, however, had both types of ulcers concurrently (142 horses).

Older horses had a higher incidence of gastric ulcers, and none of the 41 horses over 19 years of age had only glandular ulcers. The researchers pointed out, however, that EGUS is not an age-related disease but rather the prevalence of EGUS was high in older horses on this farm.

Regarding breed prevalence, 95% of Hanoverians had gastric ulcers while only 36% of Welsh Ponies did. Breed has been a suggested risk factor for ulcers from other studies, but different breeds can be used for different disciplines, which may require different exercise programs and management. The relationship between breed and discipline was not examined in this study.

In conclusion, the authors acknowledged the concerningly high rate of EGUS, be it squamous, glandular, or a combination of both, in these horses.

“Finding such a high rate of EGUS in horses reported to be asymptomatic is concerning. Horse owners should work with their veterinarian to develop a plan for managing EGUS,” said Fowler.

Certain management strategies can help reduce the risk of EGUS. These include increasing the amount of time the horse spends eating forage, feeding the horse long-stem forage before exercise, and splitting the grain ration into smaller, more frequent meals.

Treating EGUS includes administering medications and supplements designed to suppress or buffer gastric acid and feeding forages (alfalfa) that help support gastric health.

^*Zhou, K., Z. Dong, X. Zhou, B. Zhai, B. Li, J. Zhang, and F. Cheng. 2024. The prevalence of gastric ulcer syndrome in 395 horses in Jiangyin City, China, Jiangsu Province. Animals (Basel) 14(24):3636.