Development of a Rim Pad for Horseshoes Instrumented with 3D-Printed Pressure Sensors for Measurement of Gait Parameters in Racehorses

As data-driven monitoring of animal welfare becomes increasingly important, particularly in horse racing, lightweight and cost-effective integrated medical systems are required. The aim of this study is to develop a lightweight and thin instrumented horseshoe rim pad for retrofitting to a horseshoe to measure hoof loading and the movement of the center of pressure. The core of the horseshoe pad is an array of eight sensors, 3D-printed from piezoresistive and insulating materials, that were printed around the nail holes and across the entire contact surface between the hoof and horseshoe. After attaching the electrodes and cables, the mass and thickness of the instrumented horseshoe pad were 26 g and 3 mm, respectively. All eight sensors were calibrated using an electromechanical method, and calibration curves were derived. The sensor system was then mounted on an aluminum horseshoe. A load test of the entire system was used to calculate the center of pressure (COP) and its movements across the horseshoe. After mounting the instrumented horseshoe on the forefoot of a racehorse, the data obtained allowed the comparison of the forces generated between the shoe and the hoof, and of the movement of the COP in different gaits (walk, trot, canter) as well as the extraction of time-dependent parameters such as the stride frequency.