Effects of floor cooling during high ambient temperatures on the lying behavior and productivity of growing finishing pigs

Given that exposing rapidly growing pigs to high ambient temperatures can induce heat stress, which reduces their welfare and production, this study looked at the influence of floor cooling on pigs’ behavior and performance. Pens in room 1 had a solid floor (60%) and a metal slatted floor (40%). The pens in room 2 had a concrete slatted floor at the front (15%), then a convex solid floor (45%), and a metal slatted floor at the back (40%). Each room was stocked with 144 pigs with a starting weight of around 29.3 kg (±4.1 kg). The area per pig was approximately 1.0 m2. In half of the pens in each room, the floor could be cooled by cold water. The floor cooling was activated at ambient temperatures above 25°C in week 3 and above 20°C from week 7 onwards. Feed and water were accessible ad libitum. Cooling lowered the surface temperature of the solid floor (25.0°C vs. 26.8°C, P < 0.001), reduced the percentage of pigs lying on the slatted floor (15.0% vs. 22.2%; P < 0.001), and increased feed intake (2.04 vs. 1.95 kg d-1 pig-1, P < 0.01) and growth rate (753.2 vs. 720.4 g d-1; P = 0.017). Cooling and pen design affected fouling of the solid floor. The cooled pens were cleaner than the uncooled pens, and the pens in room 2 were cleaner than those in room 1. These results show that floor cooling can improve the thermal comfort and performance of intensively reared growing and finishing pigs during hot weather.