Influence of exercise on bone mineral density of immature cortical and trabecular bone of the equine metacarpus and proximal sesamoid bone.

The research article investigates the impact of different exercise levels on the bone mineral density and cross-sectional area of the equine metacarpal and proximal sesamoid bone in immature foals. The study finds that exercise has distinctive effects on bones in young foals, and over-exercising could potentially lead to an overstimulation of bone development, resulting in less active mineral deposition in the long run.

Research Methodology

• The study involved testing three groups of foals under different exercise conditions. One group was confined to a stall from birth to age 5 months (Group(box)), another similarly confined but given a daily exercise of increasing gallop sprints (Group(training)), and the last group was allowed to roam freely in pasture (Group(pasture)).
• At 5 months, some foals from each group were euthanized for analysis. The remaining foals underwent a light exercise regimen for an additional six months before being euthanized for examination at 11 months.
• The bone mineral density (BMD) and cross-sectional area (CSA) of specific bones (the left third metacarpal bone, MCIII, and the left medial proximal sesamoid bone, psb) were measured in all foals at the time of euthanasia. The measurements were done using peripheral quantitative computed tomography.

Results

• The study found that the CSA of MCIII increased as the foals aged. At 5 months, the Group(pasture) had significantly larger CSA than Group(box), but this difference was not seen at 11 months.
• While the BMD in the dorsal cortex of the bones of Group(box) was higher at 5 months than the other groups, these differences had disappeared by 11 months.
• In the proximal sesamoid bone, CSA increased with age across all groups, but no differences were seen between groups. Trabecular BMD was higher in Group(training) compared to the other groups at 5 months, but was less than Group(box) at 11 months.

Conclusions

• The findings suggest that limiting physical activity in the early months of a foal’s life can hinder normal bone development. However, this setback can be compensated for when foals are later introduced to exercise.
• On the contrary, initial exercise can increase bone mass in the third metacarpal bone and elevate bone mineral density in the proximal sesamoid bone, but over-exercising could lead to an overstimulation in bone development and reduce active mineral deposition in the long term. This points to the need for balanced, controlled exercise regimens for optimal bone development in young horses.