Risk factors for epistaxis on British racecourses: evidence for locomotory impact-induced trauma contributing to the aetiology of exercise-induced pulmonary haemorrhage.
Authors: Newton J R, Rogers K, Marlin D J, Wood J L N, Williams R B
Journal: Equine veterinary journal
Summary
Exercise-induced pulmonary haemorrhage (EIPH) remains a significant welfare concern in racehorses, yet its underlying mechanisms are incompletely understood; Newton and colleagues investigated risk factors for epistaxis (visible bleeding at the nostrils) on British racecourses between 1996 and 1998 to illuminate the pathogenesis of this condition. Using multivariable logistic regression across 1000+ race records, the researchers examined associations between epistaxis and numerous race-, horse- and start-level variables, with separate analyses for flat, hurdle, and steeplechase disciplines. Hurdle and steeplechase racing carried substantially elevated epistaxis risk compared to flat racing (where incidence was only 0.33 per 1000 starts), and across three of four models, harder ground and cumulative years of racing significantly increased risk—findings that support locomotory impact-induced trauma as a primary driver of EIPH rather than purely respiratory or cardiovascular mechanisms. Notably, horses with epistaxis finished significantly further back in races, suggesting the bleeding may impair performance. For practitioners, these results underscore the importance of track maintenance and watering regimes as practical interventions to reduce ground impact loading, particularly for jump racing where injury risk is highest.
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Practical Takeaways
- •Track watering to reduce ground hardness may be an achievable measure to reduce epistaxis incidence in racehorses, particularly in jump racing.
- •Older horses and those competing in hurdle/steeplechase disciplines warrant closer monitoring for EIPH signs.
- •Poor race performance may indicate subclinical EIPH; epistaxis should prompt investigation into underlying pulmonary haemorrhage and consideration of race type suitability.
Key Findings
- •Hurdle and steeplechase races showed significantly higher epistaxis risk compared to flat racing (0.33 cases per 1000 starts in flat races).
- •Risk of epistaxis increased significantly with harder ground conditions ('going') and accumulated years spent racing in 3 of 4 analysis models.
- •Horses with epistaxis were significantly more likely to finish in poorer positions than those without blood at nostrils.
- •Findings support locomotory impact-induced trauma as a contributing mechanism to exercise-induced epistaxis pathogenesis.