Equine and Comparative Exercise Physiology

Research Paper

Changes in shape of the Standardbred distal phalanx and hoof capsule in response to exercise

CD Cruza1 c1, JJ Thomasona1, B Faramarzia1, WW Bignella1, W Searsa2, H Dobsona3 and NB Konyera4

a1 Department of Biomedical Sciences, University of Guelph, Guelph, Ontario N1G 2W1, Canada

a2 Department of Population Medicine, University of Guelph, Guelph, Ontario N1G 2W1, Canada

a3 Department of Clinical Studies, University of Guelph, Guelph, Ontario N1G 2W1, Canada

a4 Imaging Research Centre, Brain-Body Institute, St Joseph's Healthcare, Hamilton, Ontario, USA

Abstract

The aims of this study were to determine whether the equine distal phalanx changes in shape in response to exercise and to relate any osseous changes to those in the hoof capsule. Eighteen mature Standardbred horses were randomly divided into exercise and control groups. Exercised horses were jogged on a straight track at individual mean speeds between 4 and 8 m s− 1 for 10–45 min, 4 days per week for 16 weeks. Both groups were similarly shod and pastured on the same field. Before and after the training period, each horse had digital photographs and magnetic resonance images (MRI) made of the right forehoof. Five linear measurements of the distal phalanx were recorded from the MRI and 24 measurements of the hoof capsule were made on the digital photographs. Small but significant changes in bone width (P = 0.039) were found in the controls and in two sagittal measurements of bone length (P = 0.039, 0.001, respectively) for the exercise group. These changes were slight and did not correlate with changes in shape of the hoof capsule, suggesting that the bone acts as a stable platform for supporting the capsule and withstanding loads.

(Received August 03 2006)

(Accepted November 23 2006)

Correspondence

c1 *Corresponding author: jthomaso@ovc.uoguelph.ca