Methods for screening racehorses for fracture risk

Fatal fractures in racehorses are an animal welfare issue that threaten the racing industry’s social licence. As the majority of fractures that occur in racehorses develop over time due to the accumulation of bone microdamage, there is an opportunity to develop screening methods that detect horses at risk of fracture prior to catastrophic bone failure. Important considerations when developing screening methods include determining the level of risk that is tolerable, how long the findings will be valid for, and will the method be used on its own or in combination with other screening methods. It is also important to understand the positive and negative predictive value of any screening method so that the number of false positive and false negative results can be determined. The positive predictive value decreases for all screening tests when the prevalence decreases meaning that false positives are more common for events that are rare. This is an issue when applying screening to fracture risk because fractures in racehorses remain relatively rare. Screening horses for fracture risk with advanced imaging is currently undertaken for the Melbourne Spring Racing Carnival. Evidence for the use of imaging derives from postmortem studies where pre-existing pathology that could be detected with imaging modalities such as standing CT has been identified. The monitoring of horses’ gait with wearable technology is a new methodology that shows some promise, but more work is required before it can be effectively applied as a practical screening method.

Chris Whitton BVSc FANZVCS PhD

Professor of Equine Orthopaedics Specialist in Equine Surgery Head of Equine Centre Melbourne Veterinary School Faculty of Science University of Melbourne Chris leads the Equine Limb Injury Prevention Program at the University of Melbourne Equine Centre a multidisciplinary research program funded by Racing Victoria, the Victorian State Government and the University of Melbourne, combining microstructural analysis, histopathology, biomechanics, epidemiology and mathematical modelling, dedicated to developing preventative training and management protocols for racehorses.

Chris trained as a specialist equine surgeon at the University of Sydney, Australia, gaining Fellowship of the Australian and New Zealand College of Veterinary Scientists in Equine Surgery by examination in 1995. He also completed a PhD in Carpal disease of racing horses at the University of Sydney in 1998 before moving to work at the Animal Health Trust in Newmarket, England in 1996. From 1999 to 2004 he ran his own surgical referral practice at the Newcastle Equine Centre in Australia and has worked at The University of Melbourne since 2004 as a Specialist surgeon and researcher.

He has published over 70 peer reviewed papers and contributed to 12 book chapters. He has been awarded over $13million in research grants. He regularly presents educational lectures on injury prevention to trainers in Australia and has also presented to trainers and racing veterinarians in England, Ireland, Wales, Hong Kong, Singapore, Korea, Brazil, and Uruguay.