Subclinical diseases underlying poor performance in endurance horses: diagnostic methods and predictive tests

Area of Science:

• Equine Sports Medicine
• Veterinary Internal Medicine
• Equine Performance Science

Background:

• Endurance horses experiencing poor performance often have undiagnosed health issues.
• Subclinical diseases can negatively impact athletic capabilities in horses.
• Comprehensive health evaluations are crucial for identifying performance-limiting conditions.

Purpose of the Study:

• To investigate the prevalence of subclinical diseases in poorly performing endurance horses.
• To compare the health status of poorly performing versus well-performing endurance horses.
• To identify specific health disorders associated with decreased endurance performance.

Main Methods:

• Clinical and ancillary examinations were performed on 38 endurance horses.
• Evaluations included haematology, biochemistry, exercise testing (treadmill and field), echocardiography, impulse oscillometry, and respiratory fluid analysis.
• Standardized exercise tests measured speeds at specific blood lactate concentrations (VLA4) and heart rates (V160, V200).

Main Results:

• All poorly performing horses had subclinical diseases, often multiple concurrent conditions.
• Well-performing horses were free from subclinical diseases.
• Respiratory disorders were most common, followed by musculoskeletal and cardiac problems.
• Poor performers showed reduced speeds (VLA4, V160, V200) and slower heart rate recovery.

Conclusions:

• Subclinical diseases are prevalent in poorly performing endurance horses.
• Respiratory, musculoskeletal, and cardiac disorders are key contributors to poor performance.
• Early detection and management of subclinical conditions are vital for optimizing equine athletic performance.