Association of owner-reported noise with findings during dynamic respiratory endoscopy in Thoroughbred racehorses

Dynamic respiratory endoscopy of Standardbred racehorses during qualifying races

REASON FOR PERFORMING STUDY

Examination of the equine upper airway during racing has not previously been documented.

OBJECTIVE

To describe the feasibility and appearance of the upper airways by overground respiratory endoscopic examination during racing conditions.

METHODS

Overground videoendoscopic examinations were performed on 46 Standardbred racehorses during qualifying races. Examined horses' speeds were recorded throughout the race with a portable GPS device.

RESULTS

The procedure did not interfere with performance as there were no significant differences in race times between races in which horses were examined with the endoscope in place and prior unexamined races. Airway obstructions during or after the race were documented in 21 horses. Most previously reported causes of upper airway obstruction were observed; surprisingly bilateral ventro-medial arytenoid displacement (VMAD; n = 5) was seen during exercise as frequently as dorsal displacement of the soft palate (DDSP). Although DDSP (n = 10) was the most common diagnosis made, many displacements (n = 5) occurred after the race. Horses that demonstrated DDSP after the race had slower speeds than unaffected horses during the race.

CONCLUSIONS

Racing endoscopy permits the diagnosis of upper airway obstructions without affecting performance. The occurrence of DDSP immediately after exercise may be clinically relevant. During racing VMAD may be an important anomaly.

POTENTIAL RELEVANCE

Racing endoscopy could be used to correlate the sensitivity of diagnostic endoscopy during race-training or treadmill examination. The pathogenesis and significance of VMAD deserves further investigation.