Endurance Horses: Supporting Healthy Bones

Because endurance riding is a relatively young sport compared to other equine disciplines, such as flat racing, a low volume of evidence-based data regarding health issues in endurance horses exists. This is particularly true for causes of lameness and metabolic issues, such as tying-up, which rank as the two most common causes of elimination from competition. In fact, lameness resulted in 69% of all eliminations, according to one recently published study. *

“Endurance is a high-intensity sport that requires a commitment to appropriate training that allows horses to adapt to the workload,” shared Kathleen Crandell, Ph.D.

A nutritionist for Kentucky Equine Research, Crandell went on to explain, “This is doubly important for the tissues associated with the musculoskeletal system, such as bone.”

Training results in microfractures in the bone that spur bone cells, osteoclasts, and osteoblasts to remodel bones to better handle the stress and strain induced during training. Ultimately, the remodeled bone will be capable of withstanding the repetitive concussion and remain injury-free.

“Mitigating injuries will reduce lost training days, veterinary- and drug-related expenses, and wastage in the equine industry,” Crandell emphasized.

As highlighted by Rajão and colleagues in their study, endurance riding has witnessed a dramatic increase in speed in recent years:

• Before 2002, winning speeds in the World Equestrian Games ranged from 14.8 to 17.8 km/hr (9-11 m/h);
• By 2004, the Endurance World Championships in Dubai had a winning speed of 22.7 km/hr (14 m/h);
• A world record of 24.7 km/hr (15.3 m/h) was set in 2004; and
• Speeds exceeding 30 km/hr (18.6 m/h) in the final phases of competition have been reported.

Recognizing that an improved understanding of bone responses to exercise adaptations will ultimately reduce the occurrence of musculoskeletal injuries, the researchers examined the bones of 14 Arabian horses, half of which had been trained for 4-5 years in endurance races while the other half were untrained. Researchers found the cortical bone, which makes up the outer layer of the bone, had increased density and thickness in the exercised group. The trabecular bone found in the inner aspect of the examined bones remained unchanged between the two groups.

The researchers stated, “This adaptation of the cortical bone in the exercised horses is an important factor in increasing bone resistance to exercise.”

“In an effort to support bone development in athletic horses, Kentucky Equine Research developed Triacton, which contains an assortment of highly bioavailable minerals and vitamins essential for sound skeletal development, maintenance, and improved bone density,” Crandell said.

These minerals and vitamins include a novel, highly bioavailable form of calcium, as well as magnesium, boron, silicone, iodine, zinc, and manganese, as well as vitamins A, C, D, and K.

“As an added bonus, Triacton also supports the horse’s gastrointestinal system by reducing the incidence of gastric ulcers and minimizing hindgut acidosis, both of which occur commonly in performance horses,” noted Crandell.

*Rajão, M.D., C.S. Leite, K. Nogueira, et al. 2019. The bone response in endurance long distance horse. Open Veterinary Journal. 9(1):58-64.