Proof-of-concept thermoelectrically cooled sow-cooling mat.

Heat stress reduces the welfare and performance of late-gestation and lactating sows as well as the performance of their litters. Current cooling methods have shortcomings in alleviating sow heat stress. An innovative, stand-alone, thermoelectrically cooled sow-cooling mat (SCM) that does not require an external cool water source was designed, fabricated, and tested. Water circulating beneath the aluminum tread plate to remove the sow’s heat, was cooled in a heat exchanger comprising Peltier modules, heat sinks, and fans. In two farrowing room trials comparing one sow with an SCM to a control sow with no mat, the SCM’s gross cooling capacities in Trials 1 (late-summer) and 2 (mid-summer) were 395 W and 366 W, while coefficient of performance (COP) values were 3.6 and 3.2, respectively. While lack of replicates precluded drawing conclusions regarding the SCM’s impact on sow and litter performance, some performance metrics (e.g., sow weight change (Trial 2), feed intake (Trial 2), and mean final weaned piglet weight were positive. However, the SCM’s impact on sow welfare was unclear. In an environmental chamber, with two 85-W heating pads, mat center temperatures were reduced by 5 °C and 11.7 °C in Tests 1 (baseline scenario) and 2 (bottom insulated), respectively. Final cooling capacities in Tests 1 and 2 were 146 W and 161 W, respectively, while corresponding COP values were 1.3 and 1.5. The SCM’s impact on sow and litter welfare and performance should be evaluated in a larger replicated study.