Impact of race training on volumetric bone mineral density and its spatial distribution in the distal epiphysis of the third metatarsal bone of 2-year-old horses.

This study investigates the effects of race training on the bone mineral density and its distribution in a specific bone (third metatarsal bone) of young, 2-year-old horses, using statistical analysis.

Objective and Methodology

• The study aimed to analyze the impact of race training on the density and distribution of volumetric bone minerals in young horses, more specifically within the plantar metatarsal epiphysis. This portion of the bone typically bears much of the load during racing.
• They used spatial and multiple correspondence analysis (MCA) to describe and compare these densities and distributions.
• The researchers took a 2 mm transverse peripheral quantitative computed tomography ‘slice’, from 14 2-year-old Thoroughbred fillies. Half of these horses were exercised (7) and half were kept as controls (7).
• Six regions of interest in the obtained bone ‘slice’ were examined for bone mineral density (BMDv).

Findings

• The analysis found that the bone’s response to exercise was focal and showed distinct regional differences in relation to load.
• Exercise led to the deposition of new bone within existing high density bone, leading to a greater bone fraction. This resulted in clusters of uniformly distributed high density bone and a lower proportion of lower density bone in exercised horses.
• The BMDv was statistically examined at two sites loaded by the proximal sesamoid bones using geographical information software, to understand its spatial distribution.

Implications and Further Use

• This statistical approach and MCA to studying changes in bone induced by exercise have previously been described using methods like microradiography of thin slices and block-face imaging.
• The techniques used in this study non-invasively quantify and describe such changes which can prove useful for further understanding the spatial patterns of response to load.
• This may have implications for how race training is optimized for horses to maintain and improve their skeletal health and performance.