The bone response in endurance long distance horse

Abstract

The aim of this study was to understand the bone response against the exercise adaptations to reduce the occurrence of orthopedic injuries in endurance horses. To this end, the objective of the present work was to investigate how the bone adaptation on adult equines that were trained for 4-5 yr to endurance races responds to the long-term exercise of moderate intensity by comparing to non-athlete horses. For this purpose, 14 Arabian horses were selected and divided equally into two groups; a control group formed by animals that had never practiced physical activity nor been tamed and an exercise group formed by athlete animals. Radiographs were obtained using a digital radiography system and penetrometer. The radiographs were stored and later processed to determine cortical bone thickness using the ProgRes® Capture Pro 2.5 (Jenoptik, Germany), cortical bone density using Adobe Photoshop CS6 (version 6.0, Adobe Systems Inc., San Jose, CA), and trabecular bone density using the Image-Pro Plus 4.1 (Media Cybernetics Inc. Silver Springs, MD). The EG presented an increase in cortical bone density and thickness compared to the control. This adaptation of the cortical bone in the exercised horses is an important factor in increasing bone resistance to exercise. These structural changes are related to a morphofunctional response by the bone tissue as a whole.

Keywords: Adaptation; Bone; Densitometry; Equine.

Fig. 1.. Radiographic image of the radius showing how the calibration and measurement of the cortical thickness were performed at pre-determined points, using the penetrometer as a reference measurement, with images in the ProgRes^® Capture Pro 2.5 software.

Fig. 2.. Radiographic image of the radius (A), metacarpal III (B), calcaneus (C), and carpal accessory (D) bones showing the measurement point in rectangular area (orange), compared to the density at the 10th step of a penetrometer (E).

Fig. 3.. Cross-sections of the trabecular bone of the radius (A), metacarpal III (B), calcaneus (C), and carpal accessory (D) obtained using Adobe Photoshop CS6.