Evaluation and characterisation of Passive Infrared Detectors to monitor pig activities in an environmental research building

In confined feeding operations, animal activity can affect environmental variables such as indoor gas and dust concentrations, which can have negative impact on animal health and welfare. Therefore, monitoring animal activities is important in research into the environment of animal rearing. In this study, low-cost Passive Infrared Detector (PID) motion sensors were studied to monitor pig activities in the Swine Environmental Research Building, Purdue University, USA. Special functions were programmed into custom-developed data acquisition software to process the sensor analogue output signals and provide real-time, continuous, and quantitative data, which reflected behaviour-related pig activities. Signals from the PID sensors were averaged at different time intervals for data interpretation. Data using the PID sensors demonstrated substantial differences in activity magnitudes of pigs between day and night, which confirmed diurnal patterns of pig behaviours. Short-time disturbance by operational work in the rooms could cause prolonged excitement and activities of the pigs. In addition, the study revealed that pigs were active at different times of the day as they grew up. Pigs were most active between 30 and 100 post-weaning days. Based on the results of this study, PID sensors can be used to assist in monitoring pig activities in livestock production and research into animal behaviours and welfare.