EGUS prevalent in Saskatchewan racehorses

Dr. Fernando Marqués: “It makes a difference when you show people what the (gastric) ulcer actually looks like.” Photo: Michael Raine.

A study recently completed by WCVM researchers confirms that equine gastric ulcer syndrome (EGUS) is just as prevalent in Western Canada’s racehorse population as it is in other parts of the world.

By conducting gastroscopic examinations on thoroughbred racing horses stabled at Saskatoon’s Marquis Downs, the research team determined that ulcers in the nonglandular portion of the stomach were present in 74.5 per cent of the 94 racehorses involved in the study.

EGUS is a syndrome used to describe a number of clinical symptoms including ulcers or erosions in the esophagus, stomach and duodenum. In racehorses, this syndrome is characterized by inflammation and ulceration in the nonglandular portion of the stomach. Although the physiology is not completely understood yet, extensive research is being conducted into its control and diagnosis. Studies have indicated that management practices such as intensive training and intermittent feeding — both commonly used with racehorses — can increase the incidence of the condition.

WCVM’s research team, led by large animal internal medicine specialist Dr. Fernando Marqués, carried out their examinations during the 2008 and 2009 racing seasons at Marquis Downs. Although numerous world-wide studies had already confirmed that thoroughbred racehorses are most frequently affected by the syndrome, the researchers were curious to see how Saskatchewan horses would measure up.

“It’s the fact that we only race three months of the year and the horses are in pasture for the first part of the year,” explains Marqués. “But for some reason that doesn’t change anything about the prevalence, and those results are going to help us to do more about this population of horses.”

Using a portable video endoscope, Marqués and his team explored the presence or lack of lesions in the stomach and esophagus of the Saskatchewan racehorses. In order to establish possible risk factors, the team recorded a history for each animal that included gender, age, body condition score, racing performance for the last two months, level of training, history of medical and/or musculoskeletal diseases and treatments of each horse.

Based on the gastroscopic examination, each animal was evaluated from zero to four using a grading system established by the Equine Gastric Ulcer Council in which zero indicates an unaffected animal and grade four indicates the most severe grade of gastric ulcers. Of the 94 horses examined, 70 were found to have ulcers, with the majority of them being rated as grade two in severity. None of the risk factors proved to be significant

Marqués hopes that the study’s results will make local owners and trainers more mindful that EGUS may be affecting their horses. Since the clinical signs are vague and the animals don’t show any of the characteristic signs of pain such as rolling or sweating, people tend to assume that their animals are doing well even if they do have ulcers. But Marqués points out that these animals may have severe lesions in their stomachs.

“It’s an issue of awareness,” he explains. “You can inform people that their horse has a gastric ulcer, but they think the horse is happy, it’s racing, it’s performing fine, so they think they’re doing all right. But it makes a difference when you show people what the ulcer actually looks like.”

A follow-up study now being undertaken at WCVM will use the results of this research to help determine if there is a relationship between hair cortisol concentration and the presence and severity of the gastric ulcers found in the racehorses. The WCVM researchers are guided by previous studies involving wild animals that have already validated a technique for measuring hair cortisol levels and have established a link between the hair, the cortisol in the hair and the chronic stress of the animals.

Meanwhile Marqués and his research team, who have submitted the results of their gastric ulcer prevalence study for publication, are hopeful that their efforts will result in increased efforts to prevent and treat the condition among Saskatchewan’s thoroughbred racehorse population.

“It’s just common sense to me,” says Marqués.  “If you can reduce those situations that cause discomfort in those horses and the horses are not in pain, then it makes sense that they will perform better.”

Lynne Gunville is a freelance writer and editor whose career includes 25 years of teaching English and communications to adults.