4 Effects of cooled floor pads and cooled drinking water on behavior of lactating sows under heat stress

Abstract This study was conducted to evaluate whether cooled floor pads and cooled drinking water could alleviate negative impacts of heat stress on lactating sows. Sows (n = 32; parity=1 to 6) farrowed in individual stalls in two rooms. In the treatment room, a cooling pad (56 cm×56 cm×5 cm deep) was embedded in the floor of each stall where the sow’s shoulder or chest rested while lying. The pad and water in the drinker were cooled to about 16°C and 15°C, respectively. The control room was identical except cooling pads were not operating and drinking water was at room temperature. Room temperatures were controlled at 29.4°C (0700h to 1900h) and 23.9°C (1900h to 0700h) in both rooms. Sixteen focal sows (8 per room) were video-recorded during farrowing, and days 1, 3, 7, 14, and 21 after farrowing. Videos were viewed continuously to register birth time of each piglet. Number of drinking bouts and duration of each bout were registered for 2 h (1530h to 1730h) each video-recording day. Data were analyzed using the GLIMMIX procedure of SAS. Number of piglets born was used as a covariate for analysis of farrowing behaviors. No significant difference was detected for litter size born (14.1 for control vs. 15.1 piglet/litter for treatment, SE=1.33; P = 0.61), still birth (0.6 vs. 1.1 piglets/litter, SE=0.28; P = 0.31), or birth interval (14.6 vs. 14.8 min, SE=1.78; P = 0.95). Frequency of drinking bouts (2.8 for control vs. 4.2 drinks/2h for treatment, SE=0.50; P = 0.12) and duration of drinking bouts (10.5 vs. 12.0 sec/bout, SE=0.84; P = 0.21) were not affected by treatment across observation days. However, cooled sows reduced rectal temperature (39.3 vs. 39.6 °C, SE=0.11; P = 0.04) compared to control sows, suggesting cooled sows may have experienced less heat stress. These results indicate that cooled floor pads combined with chilled drinking water could be effective in reducing heat stress in lactating sows