Using Passive Infrared Detectors to Record Group Activity and Activity in Certain Focus Areas in Fattening Pigs

SIMPLE SUMMARY: Pigs are important livestock for meat production. Because of rising demand for animal products from housing systems that enable high standards of animal welfare, solutions must be found to record and assess welfare parameters. Pigs have a wide behavioral repertoire and fixed daily routines, which offers an opportunity to detect deviations from normal behavior as a measure of welfare. In this study, we evaluated the use of passive infrared detectors (PID) for measuring group activity and activity in certain focus areas in a pen of fattening pigs. PIDs can be used to measure activity by detecting thermal changes between moving bodies and the infrared radiation they emit compared to the background. For evaluation, the data of the detectors were compared to human observation to see if the technique is able to represent the behavioral patterns of the animals correctly. The results indicate that PIDs are suitable for recording the activity of a group of pigs in a pen as well as in clearly definable areas, such as the trough. Such activity profiles obtained initial conclusions to be drawn about resting, stress, and activity phases, which can be used combined with other factors like the air temperature to assess animal welfare. ABSTRACT: Animal behavior is an important aspect in the assessment of animal welfare. Passive infrared detectors (PID), detecting thermal changes to measure activity, have already been used to record data on the behavior of groups of animals. Within this study, the suitability of these detectors for the collection of activity profiles for focused areas is further investigated. The aim was to record the activity of a group of eleven fattening pigs in a pen, as well as the activity in the five functional areas for resting, feeding, drinking, exploration, and elimination. In order to evaluate the data obtained, the behavior was video recorded for visual assessment. In addition, relevant indoor environment parameters were recorded (ammonia, air temperature, and relative humidity). For the measurement of activity by PID, strong correlations from up to r = 0.87 (p < 0.01) could be found compared to visual assessment. The results indicate that activity changes during the day and activity in defined functional areas can be recorded using PIDs. These data combined with data of climate-related sensors could serve the farmer as a monitoring tool for early detection of behavioral changes or serve as partial aspect within a Weak Point Analysis within external on-farm consulting.