Support Bone Remodeling to Avoid Fractures in Athletic Horses

Bone remodeling occurs continuously in horses to ensure the skeletal system can withstand the weight-carrying and athletic demands placed upon it.

“Bone remodeling or turnover describes the process by which cells called osteoclasts break down certain components of bone while osteoblasts deposit new bone in those areas. Where these cells concentrate their efforts depends in part on the forces being applied from exercise,” explained Peter Huntington, B.V.Sc., M.A.C.V.Sc., director of nutrition at Kentucky Equine Research.

Providing horses with requisite vitamins and minerals, such as calcium, phosphorus, magnesium, and vitamins D and K, supports bone-remodeling efforts.

In addition to a balanced diet, supplementation may be warranted. “Kentucky Equine Research has specially formulated nutritional supplements that provide these and other nutrients to support healthy bone turnover. These products have been shown to improve bone density in controlled studies,” said Huntington. “Triacton, for example, contains a novel, highly digestible form of calcium with other key minerals and vitamins in an easy-to-feed pellet. Research in racehorses and weanlings demonstrated significant improvement in bone density after feeding this supplement.”

When the rate of bone adaptation lags with the demands placed on the skeleton—as happens with overtraining, increasing exercise too quickly after a layup, or overuse—microfractures, also known as stress fractures, can occur. These tiny fractures may go unnoticed at first, as some horses do not show any unsoundness.

“Horses with microfractures are at risk of developing full fractures, some of which can be career-ending, others can be catastrophic,” explained Huntington. As an example, he relayed the findings of a recent study of tibial fractures.^* The tibia is the largest of two bones in the gaskin; the fibula is the other. The femur or thighbone is situated above the tibia with the bones of the tarsus or hock below it.

In the study, most tibial fractures occurred in young horses. The fractures occurred during training in 68% of cases, and just over half of the affected horses had never raced. Importantly, a pre-existing stress fracture was noted in 64% of cases at the time of necropsy.

“The supplements formulated by Kentucky Equine Research for bone health, including research-proven Triacton, can help support the growth of strong, healthy bones when used in conjunction with training regimes that match the horse’s level of skeletal fitness. Proper training and supplementation allow bone enough time to adapt to stress. A well-designed program avoids overtraining with excessively fast works to protect bone health. Bone needs rest periods to allow for remodeling and requires a gradual increase in training loads after detraining,” Huntington shared.

Always seek veterinary advice if your horse is lame. Advanced imaging techniques may be needed to diagnose a large number of potential bone problems and prevent catastrophic fractures during a race or event.

^*Samol, M.A., F.A. Uzal, A.E. Hill, R.M. Arthur, and S.M. Stover. 2020. Characteristics of complete tibial fractures in California racehorses. Equine Veterinary Journal. doi:10.1111/evj.13375.