Thermal environment sensor array: Part 1 development and field performance assessment

Current thermal environment (TE) monitoring and control strategies for livestock and poultry facilities require enhanced measurement capabilities to provide an optimum TE based on the animals' thermal demands. Further, techniques for combining additional parameters are needed to adequately assess the total impact of the TE on the animals. Hence, two papers introduce a spatial network of 44 Thermal Environment Sensor Arrays (TESAs), each with a custom data acquisition system (Part 1) and a technique for evaluating the TE as a function of mean body temperature difference from thermally comfortable pigs using estimated body mass and TESA measurements as inputs (Part 2). The TESAs and new thermal index were deployed in a commercial pig facility to perform a preliminary assessment of robustness and capabilities under production settings. Each TESA measured dry-bulb temperature (Tdb), black globe temperature, airspeed, and relative humidity (RH), and required a custom circuit board with a microcontroller, signal conditioning, and communication hardware. After closeout (completion of the production cycle), TESAs were validated with a reference system to determine individual time constants and assess if a significant bias correction was needed (except airspeed). Total number of usable measurements for subsequent analysis for all sensors per TESA averaged (95% CI) 202,310 (199,187; 205,437). In summary, 7% Tdb thermistor, 9% digital Tdb, and 27% RH sensors required correction after 170 d inside the facility. Utilisation of low-cost sensors, open-source software, and microcontrollers allowed this novel network to provide sufficient measurement density to promote future queries on TE data in animal facilities.