Prevalence of pharyngeal and laryngeal abnormalities in Thoroughbreds racing in Australia, and their association with performance.
Authors: Brown J A, Hinchcliff K W, Jackson M A, Dredge A F, O'Callaghan R A, McCaffrey J R, Slocombe R F, Clarke A F
Journal: Equine veterinary journal
Summary
# Editorial Summary: Upper Airway Abnormalities in Racing Thoroughbreds Understanding the clinical significance of laryngeal and pharyngeal findings in racehorses has remained elusive, largely because prevalence data in working populations are scarce and the performance implications unclear. Brown and colleagues conducted rhinolaryngoscopic examinations on 744 Australian Thoroughbreds over 35 months, documenting the presence of upper airway abnormalities and correlating findings with race performance. Of the 6.3% of horses with detectable abnormalities, three conditions warrant particular attention: epiglottic entrapment (0.9%), Grade 2 left arytenoid asymmetry (1.2%), and arytenoid mucosal ulceration or erosion (2.4%). Surprisingly, both epiglottic entrapment and arytenoid asymmetry were statistically associated with superior performance rather than impairment, whilst mucosal erosions showed no performance correlation whatsoever. These findings challenge current clinical thinking and suggest that surgical intervention for Grade 2 laryngeal asymmetry in horses performing within expected parameters may be unnecessary, though practitioners should remain cautious about extrapolating results beyond the racing context—longitudinal assessment of progression, examination under exercise conditions, and evaluation in other disciplines may reveal different clinical implications than those observed in this cross-sectional study.
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Practical Takeaways
- •Several common laryngeal abnormalities detected via endoscopy (epiglottic entrapment, Grade 2 arytenoid asymmetry, mucosal erosions) were not associated with poor race performance, suggesting surgery may not be necessary for horses performing to expectation
- •Grade 2 laryngeal asymmetry should not automatically prompt surgical intervention or raise concerns about laryngeal function in clinically performing horses
- •The presence of upper airway abnormalities at endoscopy should be interpreted in context of actual performance rather than assumed to cause impairment
Key Findings
- •Upper airway abnormalities were detected in 47 of 744 horses (6.3%), with epiglottic entrapment in 0.9% and Grade 2 arytenoid asymmetry in 1.2%
- •Epiglottic entrapment was significantly associated with superior race performance (P = 0.015), contrary to expected hypothesis
- •Grade 2 left arytenoid asymmetry was associated with superior performance (P < 0.001)
- •Mucosal ulceration or erosion of arytenoids was detected in 2.4% of horses and showed no association with impaired performance (P = 0.31)