Evaluation of Overground Endoscopy Findings in Colombian Criollo Paso Horses

The dynamic upper airway functional (URT) problems of Colombian paso horses (CPH) have not been investigated in literature up to date. These horses perform special walking gaits with high poll flexion of the neck. Our goal is to evaluate the upper airway mechanics in CPH, showing abnormal respiratory sounds and poor performance during exercise. Resting and overground endoscopy was performed in 40 CPHs. Statistical analyses were performed using the sciPy package. One-tailed Fisher exact tests were used to check for positive contingency between each pair of upper respiratory tract disorder (P < .05). Arytenoid cartilage collapse was observed in 35 of 40 cases during exercise. Among these, dynamic laryngeal collapse (DLC) was the most significant finding, but ventromedial luxation of the apex of the corniculate process of the arytenoid and recurrent laryngeal neuropathy was also observed. Dorsal displacement of the soft palate was only detected in 4 of 40 cases. DLC was significantly associated with vocal cord collapse, nasopharyngeal collapse, and medial collapse of the margins of the epiglottis, and medial collapse of the margins of the epiglottis was associated with nasopharyngeal collapse. DLC is only a typical feature in some special breeds worldwide. We suggest that the extensive poll flexion and the relatively small laryngeal lumen and high intensitivity workload are the most important predisposing factors of DLC. Ventromedial luxation of the apex of the corniculate process of the arytenoid was over-represented in our caseload, compared with other studies. Whereas, despite the intensive workload, dorsal displacement of the soft palate was relatively uncommon. We presume that this could also be tailored to the high poll flexion performed during the special gaits.