Prevalence and severity of exercise‐induced pulmonary hemorrhage in 2‐year‐old Thoroughbred racehorses and its relationship to performance

Background Little has been reported regarding the prevalence and severity of exercise‐induced pulmonary hemorrhage (EIPH) in 2‐year‐old Thoroughbred racehorses. Objectives Evaluate EIPH prevalence and severity and its association with performance, speed index, furosemide administration, race distance, and track surface. Animals A total of 830 2‐year‐old Thoroughbreds. Methods Prospective blinded observational study. Videoendoscopy was performed 30 to 60 minutes postrace at 15 American racetracks. Three blinded observers independently assigned an EIPH grade (0‐4) to each video, and prevalence and severity of EIPH were determined. Relationships of EIPH grade to performance, speed index, race distance, track surface, and prerace administration of furosemide were evaluated using Pearson's chi‐squared test for categorical variables and analysis of variance (ANOVA) for numerical variables. Multivariable logistic regression assessed relationships between EIPH prevalence and severity, respectively, and the aforementioned independent variables. A P