Risk factors for exercise-induced pulmonary haemorrhage in Thoroughbred racehorses

Summary Reasons for performing study: Risk factors for occult exercise‐induced pulmonary haemorrhage (EIPH) are poorly defined or quantified. Objectives: To investigate the importance of putative risk factors for EIPH amongst Thoroughbred racehorses in Australia. Methods: Tracheobronchoscopy was used to determine EIPH status of 744 Thoroughbred racehorses after flat racing in Melbourne, Australia. Horses were identified for study before racing, and over 50% of horses racing during the study period were examined. Statistical analysis included use of bivariate and multivariate logistic regression analysis to account for simultaneous effects of a large number of variables. Results: The only risk factor identified as associated with both EIPH ≥1 or ≥2 was ambient temperature, with horses racing at temperatures