Automatic thermal control system for finishing swine in semi-arid conditions

Swine is the most consumed protein in the world, and Brazil stands out as an important producer and exporter of this product. The South and Southeast regions of Brazil lead this production, with the Northeast region, especially the Semi-arid region, having independent farming systems and low levels of technification. These factors, combined with a climate characterized by high temperatures and high levels of thermal radiation, result in low production rates for pig farming in the region. To contribute to improving the pig production chain in the northeast of Brazil, this work aimed to develop a simple prototype for controlling the thermal environment in pig finishing stalls. The controller was programmed to activate the micro-sprinkler and ventilation system, alternating between 2 minutes of micro-sprinkling and 18 minutes of ventilation. The system was validated using three treatments: 01 - control stall (without air conditioning); 02 - stall with a micro-sprinkler system; and 03 - stall with a micro-sprinkler and ventilation system. The environmental data used to verify the Temperature and Humidity Index (THI), the Black Globe Temperature and Humidity Index (BGHI) and the Enthalpy (H) of each of the treatments, and the physiological parameters of respiratory rate (RR), surface temperature (ST) and rectal temperature (RT) of the animals were also evaluated. The air temperature, H, BGHI, THI, and RR of the animals showed the best averages for the sprinkler treatment compared to the other treatments (p<0.05). It can be concluded that the thermal controller's functionality has been proven and corresponds to the comparison made between it and certified equipment. Although the sprinkler treatment showed the best results, none of the other treatments were outside the conditions that provide high levels of thermal heat stress for these animals, and air-conditioned stalls can improve their thermal comfort levels, granting them animal welfare.