Evaluation of poor performance in racehorses using a high-speed treadmill

The study reports the results of a comprehensive clinical evaluation of 18 racehorses with a history of inadequate athletic performance. The poor performance evaluation included general physical examination and laboratory screening, respiratory examination including upper airway endoscopy at rest and during maximal treadmill exercise, cardiac examination, post-exercise serum biochemistry and bronchoalveolar lavage cytology. A definitive diagnosis was established in 15 horses (83.3%). The most frequent findings were upper respiratory tract disorders, with dorsal displacement of the soft palate being most often diagnosed (eight horses) followed by axial deviation of the aryepiglottic folds (two horses) and recurrent laryngeal neuropathy (two horses). Inflammatory airway disease was diagnosed in two horses and exercise-induced pulmonary haemorrhage in one horse. Subclinical myopathy was detected in two horses. Ten horses (55.6%) had multiple concomitant problems that may have contributed to their inadequate athletic performance; therefore, a comprehensive approach is required to diagnose the cause of decreased athletic capability.