Descriptive analysis of longitudinal endoscopy for exercise-induced pulmonary haemorrhage in Thoroughbred racehorses training and racing at the Hong Kong Jockey Club.

The research article analyzes the occurrence and impact of exercise-induced pulmonary hemorrhage (EIPH) in racehorses in Hong Kong without the use of preventative medication. It explores the scope of EIPH, its severity, and its effects on a horse’s racing career.

Research Objectives and Methods

The study aimed to analyze the prevalence and impact of EIPH in racehorses during training and races, particularly those not treated with a popular preventative medication called furosemide. The method involved:

• A retrospective study of clinical endoscopy, EIPH status, and racing records of 822 Thoroughbred geldings imported from New Zealand between 2007 and 2012.
• The horses were divided into four groups for evaluation: those diagnosed with EIPH via endoscopy (EIPH+), those observed with bloody noses (Epistaxis), those who showed no EIPH on endoscopy (EIPH-), and those which did not undergo endoscopy.

Results

The findings of the study were as follows:

• 89% of the horses had been subjected to endoscopy at least once.
• Half of the horses undergoing endoscopy were diagnosed with EIPH, with varying severity.
• Only 4% of horses experienced epistaxis.
• EIPH was most commonly diagnosed after racing, with 63% of cases.
• There was no significant difference in the proportion of EIPH+ and EIPH- horses that raced, indicating that the condition did not necessarily impact the horse’s ability to race.
• Racing career longevity was longest for the horses diagnosed with EIPH.
• The number of starts EIPH+ horses made in Hong Kong did not significantly differ from the EIPH- horses.
• EIPH+ horses had longer periods before retirement than EIPH- horses. Mild EIPH+ horses were more likely retired for other reasons, while those with severe symptoms were more likely retired due to EIPH.

Conclusion

The study concluded that EIPH is common and severity varies between individuals and between episodes in the same individual. Interestingly, they found no difference in the racing career longevity between horses with and without EIPH. The study provides important insights into the impact of EIPH on racehorses and raises questions about the need for prophylactic furosemide treatment.