Mineral and Vitamin Supplementation Including Marine-Derived Calcium Increases Bone Density in Thoroughbreds

Bone quality is important for the long-term health and soundness of performance horses. In racehorses, insufficient bone density is associated with shin soreness, an important cause of lost training time and reduced starts, as well as other aspects of bone fatigue. Risks of injury during training are associated with insufficient bone density. Research has previously identified several minerals and vitamins with an influence on bone and positive effects on bone density. Marine-derived calcium mineral complexes have been shown to improve bone density and strength in laboratory animals and humans. This study evaluated the effect of a supplement containing marine-derived calcium (Triacton™) (TA) on bone density in Thoroughbred racehorses.

Thirteen Thoroughbred racehorses in race training were studied for 90 days. The average age of the horses was 3.1 ± 0.4 years. Horses consisted of two- and three-year-olds that were beginning race training, three-year-olds which had been in active race training, and older horses returning to training after a 60- to 90-day break from active training. Horses were fed timothy hay and a fortified concentrate at levels required to maintain body weight throughout the study. The base diet supplied 64 g Ca and 42 g P/d. Seven horses received 120 g/d of TA, which supplied an additional 15 g Ca and 3g P, and 7 horses received 120 g/day of a placebo pellet (CON). The supplement contained calcium, phosphorus, magnesium, silicon, boron, copper, zinc, manganese, and vitamins A, D, K, and C. The horses were paired by age and exercise intensity and then randomly assigned to treatments. One horse from the placebo group was removed from the study because of lameness unrelated to bone development and has not been included in study results. There was no difference in average age between the two groups. Training consisted of slow and fast work. The average total distance trained by the horses at different gaits in each treatment group was measured and there was no difference in training intensity or duration between the two treatment groups.

Digital radiographs of the left fore metacarpus were taken from dorsal-palmar and lateral-medial views at 0, 4, 8, and 12 weeks of training. An aluminium step-wedge was placed in plane with the metacarpus to use RBAE as an external measure of bone density. Radiographic photodensitometry was used to measure the density of the lateral, medial, dorsal and palmar cortices of the metacarpus were measured 1cm below the nutrient foramen. The thickness of each cortex and the overall thickness and width of the metacarpus were measured. Differences due to training duration and supplementation were determined using a 2-way ANOVA.

Digital radiographs of the left fore metacarpus were taken from dorsal-palmar and lateral-medial views at 0, 4, 8, and 12 weeks of training. Over the 12-week training period, the supplemented horses showed increased dorsal and palmar cortical bone density.

This research was published in Proceedings of the Australasian Equine Science Symposium, 2018.