285. Optimizing Macroenvironment Temperature for Lactating Sows and Their Litters Using Electronically-controlled Piglet Heating Pads.

Abstract Farrowing rooms temperatures are typically managed for piglet survival, but these conditions can be suboptimal for sows, potentially reducing milk production and piglet growth. Therefore, the study objective was to determine the optimal macroenvironment temperature (TMacro) to house lactating sows and their litters when using electronically-controlled heating pads. In two repetitions, 36 lactating sows (parity = 2.2 ± 2.0) and their litters (12.4 ± 1.0 piglets/litter) were either housed in LOW (n = 12 sows and litters; 15.5 ± 0.8 °C), MID (n = 12 sows and litters; 19.9 ± 0.3 °C), or HIGH (n = 12 sows and litters; 23.1 ± 0.5 °C) TMacro. A 0.34 × 1.52 m heating pad was placed in all crates, with a controller that maintained a steady state temperature and was programmed to reduce pad temperature by 0.5 °C/d post-farrowing. Sow body weight (BW) was recorded 24 h post-farrowing, and at weaning to estimate average daily gain (ADG), and sow feed intake (FI) was recorded daily. Data loggers recorded sow vaginal temperature (TV) every 15 min until weaning. Sow ear skin temperature (TEar), shoulder skin temperature (TShoulder), and respiration rate (RR) were measured daily (0800, 1200, 1600, and 2000 h). On d 2 post-farrowing, two sentinel piglets per litter were selected by birth BW and sex and implanted with a data logger to record core body temperature (TB) every 15 min until weaning, and measured for TEar, TShoulder, and RR at the same time points as sows until weaning (20.5 ± 1.2 d of age). Litter BW was recorded at 24 h post-farrowing and in weekly intervals until weaning to estimate ADG. Data were analyzed using PROC GLIMMIX. Sow was the experimental unit for sow measures and litter for piglet measures. Overall, sow TV was reduced (P < 0.01; -0.3 °C) in MID versus LOW and HIGH sows. Sow RR was greater (P < 0.01; +32.0%) in HIGH versus LOW and MID sows. Sow TEar and TShoulder were reduced (P < 0.01; -1.7 °C and -2.5 °C, respectively) in LOW versus MID and HIGH sows and reduced in MID (-1.2 °C and -1.7 °C, respectively) versus HIGH sows. Litter TB was reduced (P < 0.01; -0.1 °C) in HIGH versus LOW and MID piglets. Litter RR was decreased (P < 0.01; -7.5%) in MID versus the HIGH piglets. Litter TEar and TShoulder were reduced (P < 0.01; -0.6 °C and -0.7 °C, respectively) in LOW when compared to MID and HIGH piglets and reduced in MID (-0.7 °C and -0.7 °C, respectively) versus HIGH piglets. No other differences were observed with any comparison (P > 0.05). In summary, HIGH TMacro increased thermoregulatory responses of sows but had no impact on piglet growth when piglets were provided with an electronically-controlled heating pad.