Can accelerometer devices be a reliable tool for measuring horse lying behavior? A pilot study

Sleep plays a crucial role for animal welfare due to its significant biological function of restorative properties. To achieve paradoxical sleep, horses need to lie down, therefore lying has been reported as an effective animal-based indicator. Accelerometer devices are commonly used in cattle to continuously monitor lying behavior. The aim of this study was to understand whether accelerometers attached to the leg can be a reliable device to accurately monitor horse lying behavior. As a pilot, three horses were equipped with a MSR145 Data Logger to monitor the daily duration of lying behaviour, as well as the length and frequency of lying bouts over a period of 5 consecutive days. The accelerometer was positioned within the stable boot on the left front limb of the horses when they were housed in single boxes. The data were extracted, checked for the positioning of the sensor and the data variability, and then analyzed in continuous using the raw data time series. The accelerometer was always mounted correctly and there was a modest data variability on the daily lying time. Mean lying time over 24 hours was 171 minutes with 3 to 5 lying bouts of mean duration of 30 minutes each. Horses showed an individual lying down pattern that was similar over the 5 days. Our preliminary results showed that the accelerometer can be a reliable, useful, and well accepted tool to monitor lying behavior of horses kept in single box. These preliminary results open the possibility to further investigation regarding horse athlete sleep patterns, especially during traveling for competitions.