Our analysis was based on approximately 300,000 race starts provided by two of the
four official racecourses in that country between 2006 and 2015. Logistic regression was
used to identify variabes associated with two outcomes: fatalities and MSI. All available
variables were examined at the univariable level, and a final multivariable model was
developed to identify multiple risk factors.
A number of risk factors related to the horse and its racing history; the race; and
declared authorized medication were identified as being associated with one or both
outcomes of interest. For example, a horse that was declared to run under furosemide and
fenilbutazone was more likely to sustain a fatality than a horse declared to run only with
furosemide or with no medication at all. And longer races were associated with an increased
risk of both MSI and fatalities.
We believe that this is the first study to clearly demonstrate the relationship
between medication regulations and equine welfare. These results may encourage new
medication policies, that seek to optimize welfare in Thoroughbred racing in South America.