Validation of a sensor-based automatic measurement system for monitoring chewing activity in horses

• It is feasible to use the automatic measurement system successfully in horses.
• Good accuracy between visual observations and automated data recording.
• Great benefit of the system is the non-invasive method to monitor jaw movements.
• Automatic identification of lip movements without jaw movement could further improve accuracy.

The aim of this study was to determine the feasibility of using a jaw movement measuring system developed for cattle, the “RumiWatchSystem”, on horses. The system records the chewing activity and consists of a noseband pressure sensor, integrated into a halter, and a software package. In order to investigate the accuracy of the system, 10 horses (5 mares, 5 stallions) were equipped with the device. Additionally, they were observed visually as a reference method, while feeding three different feeds (hay, haylage and concentrate). To ensure similar conditions, the horses were stabled individually and fed twice daily with roughage and twice or three times with concentrate. The results of the visual observation were compared to the automatic measurement as an evaluation of the accuracy of the automatic measurement system.The overall agreement of the observed and automatically measured data within all feedstuffs was 93%. The agreement of feeding roughage was even higher with 95%. However, for concentrate the visual observations and automatic measurements agreed only in 91.4%. The decreased agreement compared to the roughage is due to the high sensitivity of the automated system. Horses tend to display a high amount of lip movements towards the end of the concentrate intake. This is different compared to cattle behaviour and their feeding regime. However, the system was not specifically adapted to horses so far and can be optimized in order to improve accuracy. Consequently, the system has a high potential to become a reliable tool for research and practical use.