284. Impact of Use of Rubber Mats on Thermal Comfort of Gestating Sows in Prop 12 Compliant Barns.

Abstract Current legislation requires gestating sows to be placed in group housing. This has given rise to higher incidence in lameness. Flooring is one of the most important components of animal housing as far as animal health and welfare are concerned. In swine, the most common type of flooring used in Proposition 12 gestation barns is slated concrete. Known for its durability, thermal conductivity and strength, concrete also presents disadvantages of high prevalence of lameness. The use of rubber mats flooring in Prop 12 housing provides potential for reducing lameness but with it presents disadvantages of thermal discomfort as rubber is a poor conductor of heat. The effect of rubber mats on thermal comfort in Prop 12 barns has not been documented. The objective was to investigate the impact of rubber mat flooring on the thermal comfort of gestating pigs in Prop 12 gestation barns. A total of 600 sows were enrolled in the study for the entire post-insemination period (∼15 weeks), from May-August, and randomly assigned to two treatments:1) Group pen with rubber mat flooring (Mat; n = 10 pens;30 sows/pen), 2) group pen with concrete flooring (Con; n = 10 pens;30 sows/pen). Thermal images of side views of the sows, as well as a single ear, were captured using Teledyne FLIR E8 Pro. The ambient temperature was also measured on each day of data collection using data loggers. All thermal images were analyzed using FLIR ResearchIR Max 4.4 software. The individual animal surface temperatures were summarized by two different regions of interest 1) average temperature within an oval oriented over the trunk of the pig, and 2) utilizing the broken line tool, temperatures down the center of the ear were captured. A cubic equation was used to describe the response of the sow’s surface temperature to changes in ambient temperature (Microsoft Excel, Redmond, WA 98052). A breakpoint analysis was completed on each of the cubic responses using the first derivative. GLIMMIX Procedure in SAS was used to analyze ear temperatures with fixed effects of Treatment, ambient temperature, and Point. Surface temperatures were significantly affected by ambient temperature, and response equations were developed. Breakpoint analysis revealed a threshold, thought to equate to maximum value of thermal neutral zone, ranging from 19.56 ºC to 26.08 °C for Concrete treatment and 20.79ºC to 25.93 °C for Rubber mats treatment. A tendency was observed in ear temperatures between the two treatments:(33.94 ± 0.23 vs 34.34 ± 0.22 P = 0.1) for concrete and rubber mats respectively. These results indicate that pigs with rubber mats are more likely to experience maximum threshold at a much lower ambient temperature compared to the pigs in concrete flooring. Further research is required to determine the accuracy of the thresholds.