Horses are obligate nasal breathers, meaning they can't breathe through their mouths, even when performing under massive physiological stress. The nasopharyngeal region also relies only on muscle strength to maintain stability.
During exercise, when pressures on the floor of the nasopharynx and within the larynx are highest, the structures may collapse, causing horses to develop forms of dynamic upper airway obstruction. This can compromise respiratory function and gas exchange in the lungs, hindering performance.
A new study has found that if a horse's epiglottis looks flaccid on X-ray, it most likely also suffers from dorsal displacement of the soft palate.
A team of researchers at the University of Milan, led by Dr. Chiara Maria Lo Feudo and veterinarian Dr. Federica Collavo, investigated the upper and lower airways of 360 Thoroughbred and Standardbred racehorses that had been referred to the Equine Sports Medicine Unit of the Veterinary Teaching Hospital of the University of Milan between 2000 and 2021. Each horse had poor performance or had unusual respiratory noises.
The team hoped to find an association between resting airway endoscopic findings and the development of the disorder. The researchers looked at epiglottis size, airway inflammation, and for any evidence of exercise-induced pulmonary hemorrhage. Each horse had an airway evaluation and treadmill work completed.
The scientists determined that the only marker associated with dorsal displacement of the soft palate was the flaccid appearance of the epiglottis. There was no relation between the condition and inflammation or epiglottis length. The horses with dynamic upper airway obstructions did not appear to be more prone to lung bleeding.
The results suggest that the epiglottis may contribute to upper airway stability based on its conformation, not on its dimensions. They noted that inflammation does not predispose horses to the onset of upper respiratory obstruction. The condition was more common in Thoroughbreds than Standardbreds, confirming that the breed may be predisposed to the condition.
Read the full study here.
Read more at HorseTalk.
The post Flaccid Epiglottis And Exercise-Related Airway Issues In Racehorses appeared first on Horse Racing News | Paulick Report.
