Suitability of solar-powered acceleration and global positioning devices for remote monitoring of equine welfare - a case study

This study evaluated solar-powered GPS and accelerometer devices for monitoring equine welfare. Two devices, a research device (RD) and an ear tag-like device (ETD) originally developed for cattle, were tested on horses mounted on a halter or neck collar. The RD collects high-frequency raw data for developing behavior classification algorithms, while the ETD transmits limited daily data points for low-maintenance, long-term monitoring. Data were collected from 20 group-housed horses during winter 2023/2024, though individual animals were monitored for limited periods. Devices were compared with battery-powered GPS and accelerometer references, focusing on (1) safety and behavioral compatibility, (2) energy supply and transmission stability, and (3) behavioral evaluation. No major welfare concerns were observed; the RD occasionally interfered with natural behaviors and is unsuitable for unsupervised use, whereas the ETD was generally safe. Initial ETD data yield was low under low-light conditions but improved after pre-charging. GPS accuracy was sufficient for general positioning, although ETD showed lower temporal resolution. Accelerometry data agreed with RD and independent loggers. RD enabled locomotion classification, movement quantification, and potential detection of rare events (atonic collapses). Leg-mounted sensors classified locomotion and lying accurately, while neck-mounted sensors detected lateral but not sternal recumbency. Combining RD data with labeled observations supports development of equine-specific algorithms. ETD is suited for herd-level monitoring, and RD enables high-resolution behavioral analysis. These results demonstrate the feasibility of adapting cattle-derived technology for equine welfare, providing a foundation for low-impact, continuous monitoring, and supporting the development of cost-effective, scalable sensor-based systems in precision livestock management.