Prevalence of pharyngeal and laryngeal abnormalities in Thoroughbreds racing in Australia, and their association with performance.

This research focuses on how certain abnormalities within the upper airway of Australian racehorses affect their performance. The results suggest that specific abnormalities like epiglottic entrapment and laryngeal asymmetry do not have an adverse impact on their racing performance, suggesting that surgical correction may not always be necessary.

Research Objectives and Methods

• This study aimed to determine the prevalence of upper airway abnormalities in thoroughbred racehorses in Australia and assess their potential impact on horse performance. The premise was that such abnormalities could be linked to poor racing outcomes.
• The research involved studying horses in Victoria, Australia, and relied upon a method known as rhinolaryngoscopy. This endoscopy procedure allows examination of the larynx (voice box) and the pharynx (parts of the throat), identifying any potential abnormalities.

Findings and Results

• The researchers conducted single instances of rhinolaryngoscopy on each of the 744 horses over the course of 35 months.
• Of these, 50 upper airway abnormalities were detected in 47 horses, which constitute about 6.3% of the total. This percentage is within a 95% confidence interval of 4.7-83%.
• Epiglottic entrapment was found in 7 horses (0.9% of the total), and this condition was significantly associated with superior performance.
• Grade 2 asymmetry of the left arytenoid cartilage was found in 9 horses (1.2% of the total). This abnormality also correlated with superior performance.
• The presence of mucosal erosions or ulcers on the axial surface of one or both arytenoids was noted in 18 horses (2.4% of the total). However, this was found not to alter exercise performance.

Conclusions and Recommendations

• The results indicate that abnormalities such as epiglottic entrapment and Grade 2 laryngeal asymmetry do not necessarily impair the racing performance of Thoroughbred horses.
• This implies that undertaking surgical interventions to correct such conditions may not always be required, particularly if the horse is performing as expected.