Influence of thermal environment on sows around farrowing and during the lactation period

Our objective was to investigate the effects of floor heating duration (HEAT: 35 degrees C for 12 or 48 h) after birth of first piglet (BFP) under different room temperatures (ROOM: 15 degrees C, 20 degrees C, 25 degrees C) on sows during farrowing and lactation. The study included 8 to 11 repetitions for each combination of ROOM and HEAT. There were no treatment effects on indicators of birth problems (duration of parturition, interbirth intervals, umbilical cord lactate concentration), BW changes of the sow, and litter size and weight until weaning. Sows at 15 degrees C compared with 20 degrees C and 25 degrees C spent more time nest building (P = 0.015). The feed intake was reduced the first 7 d after farrowing in sows at 25 degrees C (P = 0.014); however, both daily feed intake (P = 0.018) and water consumption (P < 0.001) of these warm sows exceeded that at lower temperatures during the last part of the lactation. Sows at 15 degrees C received more medical treatments until weaning at HEAT = 48 h only (ROOM and HEAT interaction, P = 0.005). Room temperature influenced prefarrowing water consumption (25 degrees C > 20 degrees C and 15 degrees C; P < 0.017), sow surface temperature (15 degrees C < 20 degrees C < 25 degrees C; P < 0.001), respiration rate (25 degrees C > 20 degrees C > 15 degrees C; P < 0.001), and rectal temperature during the first 12 h after BFP (15 degrees C < 25 degrees C; P = 0.009); additionally, long floor heating duration (HEAT = 48 h) increased the respiration rate by 50% d 1 and 2 after BFP (P < 0.001). The proportion of lying time on the unheated slatted floor increased with room temperature (P < 0.001) and, transiently, also for the HEAT = 48 h treatment 13 to 48 h after BFP (P < 0.001). The majority of piglets (82% to 95%) were born on the heated solid floor, regardless of room temperature (P = 0.46). Sows spent approximately twice as much time standing and walking at 15 degrees C during 13 to 48 h after BFP at HEAT = 12 h only (ROOM and HEAT interaction; P = 0.002). In conclusion, long-term indicators of reduced sow performance were unaffected by room temperature, probably because the farrowing and lactating sows in the current pen design were able to perform thermoregulatory behavior and successfully adapt to room temperatures between 15 degrees C and 25 degrees C.