Videoendoscopic evaluation of the upper respiratory tract in 93 sport horses during exercise testing on a high-speed treadmill.

This study used videoendoscopy to investigate upper respiratory tract (URT) issues and obstructions that occur during physical exercise in sport horses, a common cause of poor performance or abnormal breathing noise in these animals. The study concluded that videoendoscopy during exercise is valuable in equestrian sports for diagnosing such issues, many of which may not be detectable at rest.

Methodology

• The researchers performed videoendoscopy on the URT of 93 sport horses, both at rest and during high-speed treadmill exercise. This test allowed the researchers to visualize and assess the horses’ URT during activity.

Results

• 77% of the tested horses were diagnosed with dynamic airway obstructions, which refers to a blockage that happens during exercise but is not usually present when a horse is at rest. These obstructions were often complex in nature.
• The most common forms of dynamic obstructions were soft palate dysfunction (found in 54% of the horses), dynamic laryngeal collapse (in 38%), axial deviation of the aryepiglottic folds (in 24%), and pharyngeal wall collapse (in 18%). These conditions all involve different parts of the horse’s throat and air passages.
• In most of the horses, there were no notable abnormalities identified when they were at rest.
• Enforced poll flexion, a position in which the horse’s head and neck are flexed, was shown to contribute to URT dysfunction in 24% of the cases.

Conclusion

• The findings reveal that dynamic obstructions of the URT during exercise are a common cause of diminished performance and abnormal respiratory noises in sport horses. These issues are often not observable when the horses are at rest.
• The study underlines the value of videoendoscopic evaluation of the URT during physical exercise for horses used in equestrian sports. It provides crucial insights into URT dysfunctions that affect performance during submaximal exercise, which is typical in many equestrian competitions.