Overground endoscopy in 311 Thoroughbred racehorses: findings and correlation to resting laryngeal function.

The research studied 311 thoroughbred racehorses using overground endoscopy to determine any correlation between dynamic upper airway obstructions and laryngeal function while resting. The results showed that multiple dynamic upper airway obstructions commonly associated with abnormal exercising respiratory noise were prevalent in horses investigated for poor performance. The study underlines the importance of overground endoscopy in accurately diagnosing the nature of these obstructions.

Methodology

• The researchers conducted a retrospective analysis of horses introduced for overground endoscopy (OGE) between 2010 to 2014. The reasons for examination were either perceived poor performance or a history of abnormal exercising respiratory noise.
• The researchers reviewed the horses’ information, including their history and findings from both resting laryngeal endoscopy and OGE.

Results

• Out of the 311 examinations reviewed, dynamic upper airway obstructions (DUAO) were found in 249 horses.
• The 210 male horses were composed of colts and geldings. Out of them, 121 had a condition named arytenoid cartilage collapse (ACC), and 111 experienced vocal fold collapse (VFC).
• Among the 101 female horses, 25 experienced a condition called intermittent dorsal displacement of the soft palate (DDSP).
• The researchers found a resting laryngeal function grade 4 in 121 out of the 311 horses in the study population and 92 out of 210 males.

Correlations and Association

• Significant correlations were found between horses with lower resting arytenoid abduction ability and dynamic ACC and between higher resting arytenoid abduction ability and DDSP.
• A positive association was demonstrated between abnormal exercising respiratory noise and the presence of DUAO. This suggests that when the horses exercise and produce an unusual sound, it likely reveals the presence of DUAO conditions.

Conclusion

• The findings of multiple DUAOs associated with abnormal exercising noise were common in horses examined for poor performance.
• This study emphasizes the necessity of OGE in accurately diagnosing DUAO linked with poor performance in horses. The diagnosis made through resting endoscopy alone may prove less comprehensive and accurate, highlighting the importance of OGE.