Incidence and risk factors associated with exertional rhabdomyolysis syndrome in National Hunt racehorses in Great Britain.
Authors: Upjohn M M, Archer R M, Christley R M, McGowan C M
Journal: The Veterinary record
Summary
# Editorial Summary: Exertional Rhabdomyolysis in National Hunt Racehorses Exertional rhabdomyolysis syndrome represents a significant welfare and economic concern in National Hunt racing, yet its epidemiology and risk factors had not been systematically investigated in British yards. Upjohn and colleagues surveyed 51 National Hunt racing establishments (encompassing 1,140 horses) via telephone interview and conducted a detailed case-control study in eight yards where cases had been confirmed through serum muscle enzyme analysis. The research revealed an incidence of 6.1 cases per 100 horses annually, with 55% of yards reporting at least one affected horse during the 12-month study period. Sex, gallop length during training, and horse type (steeplechaser, hurdler, or bumper/unraced) emerged as significant risk factors, whilst temperament, age, and athletic ability (as measured by Timeform rating) showed no meaningful association with syndrome development. These findings suggest that training intensity and protocol merit particular attention in prevention strategies, and that susceptibility may be partly determined by discipline-specific demands rather than individual performance capacity, offering farriers, veterinarians and trainers practical targets for reducing incidence through evidence-based modifications to exercise prescription and yard management.
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Practical Takeaways
- •Trainers should recognize exertional rhabdomyolysis as a common condition affecting over half of National Hunt yards; be alert to sex-based differences and monitor individual horses accordingly
- •Training gallop length appears modifiable—review current protocols and consider that longer gallops may increase syndrome risk in susceptible animals
- •Type of horse discipline (steeplechaser vs. hurdler vs. bumper) influences risk; tailor conditioning programs based on racing category rather than relying on temperament or Timeform rating as predictors
Key Findings
- •Overall incidence of exertional rhabdomyolysis syndrome was 6.1 cases per 100 horses per year in National Hunt racehorses
- •55% of surveyed yards reported at least one case during the study period
- •Sex, average length of training gallop, and horse type (steeplechaser, bumper/unraced, or hurdler) were identified as significant risk factors
- •Temperament, age, and Timeform rating showed no significant associations with syndrome development