Sow Location Within Farrowing Room Impacts Reproduction During Heat Stress

Mark Knauer, Zack Peppmeier, Suzanne M Leonard

The objective was to evaluate the impact of sow location, within farrowing room, on reproduction during periods of heat stress. Data were collected on 1,866 sows at a 3,600-sow commercial farm in eastern North Carolina from May to August 2021. In the farrowing buildings, evaporative cool cell pads cooled the air entering the hallway. Cooled air, from the hallway, then entered the farrowing rooms through inlets at the front of the room and was pulled through the room by fans in the back of the farrowing room. For data analysis, each farrowing room was divided into four zones. Zone 1 included the sows at the front of the farrowing room near the inlets letting in cooled air. Zone 4 included sows at the back of the room where air exited the building through fans embedded within the wall. Zones 2 and 3 were intermediate. Each farrowing room on the farm housed between 18 and 36 sows. After farrowing, sows had ad libitum access to the lactation diet. Traits included piglet survival (number weaned ÷ total number born) the percentage of sows conceiving by 7 days after weaning, subsequent total number born, subsequent number born alive, subsequent stillborns, sow caliper score prefarrow, sow caliper score at weaning and sow caliper lactation loss. Results are shown in Table 1. Piglet survival was greater (P < 0.05) for sows that farrowed at the front of the room near the cool air inlets. Similarly, litter weaning weight was heavier (P < 0.05) near the cool air inlets relative to the back part of the farrowing room. The percentage of sows that conceived by 7 days after weaning, and farrowed, was linearly associated (P < 0.05) with farrowing zone. Sows near the cool air inlets lost less (P < 0.05) body condition and farrowed more (P < 0.05) piglets in the subsequent litter relative to sows in the back of the farrowing room. Results showed sows that farrowed at the front of the farrowing room lost less body condition, had greater piglet survival, heavier litter weaning weights and were more likely to be rebred and conceive by 7 days after weaning relative to sows farrowing in the back of the farrowing room.