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Measuring Stress: Is it All About the Hair?

posted by Horse Owner Today    |   December 23, 2010 21:25


The hair-raising atmosphere of a thoroughbred racing venue is thrilling for spectators and an accepted way of life for people whose livelihoods depend on the racing industry.

But what about stress levels of the highly trained animals at the centre of this multi-million dollar industry?

That’s a key concern for Dr. Fernando Marqués of the Western College of Veterinary Medicine’s Department of Large Animal Clinical Sciences. The clinical researcher recently completed a study confirming the high prevalence of nonglandular gastric ulcers, a potential source of stress, among Saskatchewan thoroughbred racehorses.

 In a natural progression from his gastric ulcer study, Marqués has teamed up with large animal medicine resident Dr. Alberto Ruiz as well as Drs. David Janz, Bryan Macbeth and Marc Cattet of the WCVM. Supported by the College’s Equine Health Research Fund, the new project is designed to investigate the potential relationship between the presence and severity of gastric ulcers and the concentration of hair cortisol in thoroughbred racehorses.

After talking with Janz about his findings that link high hair cortisol concentrations to long-term stress in polar bears and caribou, Marqués decided to seize the opportunity to investigate cortisol concentrations in the animals he and his team were evaluating for gastric ulcers: “As we were endoscoping the horses, we pulled some hair from them and took serum samples so that we could analyze the cortisol levels afterwards.”

Ruiz, who took on the cortisol study as his Master of Veterinary Science (MVetSc) project, is now working on the analysis technique with Janz.

“Since the hair of polar bears and caribou and horses is very different and they come from very different environments, we’re trying to modify the technique to develop one that works for horses,” says Ruiz.

Using this customized cortisol enzyme immunoassay, the researchers plan to compare serum cortisol concentrations, indicators of short-term stress, to hair cortisol concentrations, indicators of long-term stress. Most importantly, they hope to establish a relationship between the cortisol levels and the presence and severity of gastric ulcers.

“If the cortisol increases with stress and if horses with severe gastric ulceration experience pain, then they may have higher cortisol levels than horses with no gastric lesions,” explains Ruiz. “Although we won’t be able to diagnose gastric ulceration just from the results, they may help us to identify horses that are more likely to have gastric ulcers.”

The researchers are hopeful that their study will eventually lead to an inexpensive screening test for cortisol concentrations that will be easily accessible to veterinarians and their clients. Using that information, owners could then make decisions about adjusting management techniques such as feeding frequency and training intensity.

Veterinarians could also greatly benefit from knowing which animals or groups of animals that are most likely affected with gastric lesions. A gastroscopy, the only reliable test for diagnosing gastric ulcers, is expensive and invasive. But cortisol measurements could be used to determine which animals may benefit from direct examination of the stomach. Plus, if a link is established between the cortisol levels and the severity of the lesions, veterinarians could use that information to determine a treatment protocol.

Ruiz points out that a screening device leading to early diagnosis of gastric lesions or ulcers could have a huge economic impact on the entire equine industry: “Gastric ulceration continues to be of great interest to horse owners and veterinarians. New studies are being published each year that are helping us understand the importance of treatment and prevention of gastric ulcers in horses. If we can discover ways to decrease diagnostic costs and improve on our ability to assess stress in horses, everyone should benefit.”


Reprinted with permission of Horse Health Lines, news publication for the Western College of Veterinary Medicine’s Equine Health Research Fund. Visit www.ehrf.usask.ca to sign up for Horse Health Lines’ e-newsletter.


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Gastric Ulcers Prevalent in Saskatchewan Racehorses

posted by Horse Owner Today    |   December 23, 2010 21:12

By Lynne Gunville



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. She and her husband live at Candle Lake, Sask.


Reprinted with permission of Horse Health Lines, news publication for the Western College of Veterinary Medicine’s Equine Health Research Fund. Visit www.ehrf.usask.ca to sign up for Horse Health Lines’ e-newsletter.


Click here http://www.horseownertoday.com/vendor.aspx?vid=12 to view Western College of Veterinary Medicine’s www.HorseOwnerToday.com verified vendor advertisement.