A major new study by the Royal Veterinary College (RVC) has identified more than 100 genes potentially linked to fracture risk in Thoroughbred horses. These groundbreaking findings could pave the way for further research into genetic predisposition, helping to enhance equine health and reduce injury rates in the sport.
Bone fractures are a significant concern in Thoroughbred racing, with the immense forces exerted on a horse’s bones during competition making them particularly susceptible. Each year, approximately 60 racehorses in the UK are euthanised due to severe fractures. While environmental factors have been widely studied, this latest research focuses on genetic components that may predispose certain horses to higher fracture risk.
Key Findings and Scientific Approach
Led by Dr. Debbie Guest, Senior Research Fellow at the RVC, researchers applied a polygenic risk score model to assess fracture risk. The study involved creating bone-forming cells from stem cells of horses identified as high and low risk. By measuring gene expression in these cells, scientists identified 112 genes with different activity levels in horses with a higher predisposition to fractures.
The research revealed that many of these genes play a role in regulating the bone matrix, which is crucial for maintaining bone strength and resilience. However, a significant number of the genes identified have never been studied in relation to bone health before, highlighting the need for further investigation.
This study builds on previous RVC research, which found that Thoroughbreds with a high genetic risk of fracture had lower expression of the collagen type III gene. This gene is essential for normal bone formation, and a variation in its DNA sequence affects the amount of collagen III produced, potentially weakening bone structure.
Future Research and Practical Applications
Ongoing studies are now underway to validate the genetic risk-scoring system in a new cohort of horses. Researchers are also using the same cell-based model to identify additional genes and biological processes that contribute to fracture susceptibility. The long-term goal is to provide veterinary practitioners and breeders with tools to assess and mitigate risk, ultimately improving racehorse welfare and performance.
Dr. Debbie Guest emphasised the importance of these findings:
“Bone fractures remain a major issue in Thoroughbred racehorses, despite efforts to reduce environmental risks. Our study confirms that genetic factors play a crucial role in fracture risk. By identifying new genes that influence bone composition, we can better understand why some horses are inherently more vulnerable and explore new ways to prevent injuries.”
Industry Impact and Next Steps
The study was funded by the Horserace Betting Levy Board, the Anne Duchess of Westminster Charitable Trust, and The Alborada Trust. Findings from this research could inform new breeding strategies, training protocols, and potential interventions to enhance bone strength in racehorses.
British racing authorities and veterinary experts are closely following these developments, as improved genetic understanding could lead to significant advancements in horse welfare. Future studies will aim to refine the genetic markers for fracture risk and develop practical applications for the industry.
The full study, ‘Identification of a global gene expression signature associated with the genetic risk of catastrophic fracture in iPSC-derived osteoblasts from Thoroughbred horses,’ is available via PubMed.
For further details on the research and ongoing studies, visit the Royal Veterinary College website.
