In the Midwest there are several racetracks--featuring both Thoroughbred and Quarter Horse racing--that sometimes slide under the radar of the mainstream racing community. But like all other tracks around the nation, these venues see wins, losses, and, unfortunately, catastrophic musculoskeletal injuries. Andrea L. Beisser, BA, and her colleagues analyzed the circumstances surrounding catastrophic musculoskeletal injury (CMI) at three tracks in these regions, and she presented the study results at the 2010 American Association of Equine Practitioners' Convention, held Dec. 4-8 in Baltimore, Md.

Beisser and her team evaluated a wide range of variables in order to obtain the most complete data set possible from Prairie Meadows in Iowa, The Woodlands in Kansas, and Remington Park in Oklahoma. She noted that the team was able to secure necropsy reports and race records on 130 Thoroughbred fatalities and 50 Quarter Horse fatalities.

They found that the average CMI rate of the three tracks was 1.46 fatalities per 1,000 starts. The average CMI count for Thoroughbreds was 1.48 per 1,000 starts, and Quarter Horses averaged 1.36 CMIs per 1,000 starts. Individually, all three tracks delivered similar results. Only dirt tracks were used in the study.

Beisser's team found that at the Midwestern tracks the highest frequency of Thoroughbred CMIs occurred in claiming races, while the majority of Quarter Horse CMIs happened in stakes or handicap races.

The average distance a Thoroughbred ran before sustaining a CMI was six furlongs, while the average distance a Quarter Horse ran was just 350 yards. Beisser explained that the difference in distance covered was likely due to the fact that Thoroughbreds generally run longer races than Quarter Horses do.

Additionally, the most common location of CMIs in Thoroughbreds was in the left forelimb, with nearly 57% of injuries occurring in that leg. Quarter Horses, however, saw 60% of CMIs take place in the right forelimb. Both Thoroughbreds and Quarter Horses travel the same direction during races.

The most common type of CMI reported in Thoroughbreds was a sesamoid (small bones behind the fetlock) fracture; such fractures were the cause of nearly 39% of the fatalities reported. Beisser added that humeral (forearm bone) fractures were overrepresented in Quarter Horses.

Beisser reported that when she and her colleagues compared 3- and 4-year-old Thoroughbreds, the 4-year-old Thoroughbreds were twice as likely to sustain a CMI. Additionally, she stated that the sex of the horse was not a significant factor in the study.

Beisser relayed that the Quarter Horse population of the study was small, so the results should be interpreted with caution.

"The differences identified between Thoroughbred and Quarter Horse CMIs should allow regulatory veterinarians at mixed meets to focus the evaluations on horses and anatomical regions at greatest risk," Beisser wrote in the study.

"Racing in smaller Midwest jurisdictions has similar injury rates to larger jurisdictions," said Scott McClure, DVM, PhD, Dipl. ACVS, one of the co-authors on the study. "When we are pursuing further work in this area, we may want to consider the differences between Thoroughbreds and Quarter Horses."

About the Author

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 eventing with her OTTB, Dorado.

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