Assessment of the exercise tests used during overground endoscopy in UK Thoroughbred racehorses and how these may affect the diagnosis of dynamic upper respiratory tract obstructions.

The research was conducted to assess the exercise test parameters used in overground endoscopy of UK Thoroughbred racehorses, and to understand their potential impact on diagnosing upper respiratory tract blockages.

Objective of the research

The research sought to:

• Document the parameters used in exercise tests during overground endoscopy in UK Thoroughbred racehorses.
• Examine the possibility of these parameters affecting the diagnosis of upper respiratory tract (URT) obstructions.

Methodology of the research

The method involved:

• Recording the parameters used in the exercise tests and the endoscopic observations of the URT during these exercises for 140 Thoroughbred racehorses under investigation for abnormal respiratory noise and/or poor athletic performance.

Results of the research

Results showed that:

• The parameters used in the exercise tests varied significantly between horses.
• It was easiest to replicate the presenting complaint in horses showing a history of abnormal noise during training, and most difficult in horses undergoing investigation for poor performance without any abnormal noise.
• No correlation was found indicating that the presence or absence of a URT obstruction was linked to the parameters of the exercise test.
• Horses referred due to abnormal noise during racing were more likely to show a dorsally displaced soft palate (DDSP) when tested over longer distances.

Conclusion of the research

The research concluded:

• It is challenging to standardize exercise tests in the field due to the use of multiple premises and significant differences between training gallops and racecourses.
• It was not possible to establish a set of exercise test protocols appropriate for all Thoroughbred racehorses.
• Current best-practice advice for horses presenting abnormal noise during a race or poor race performance is to reproduce race conditions as closely as possible during testing.
• Horses racing over longer distances may require testing at a circular gallop (e.g., a racecourse) if only short gallops are available at their trainer’s premises.