LAUSR

117 0.72 kg/d greater ADFI and 6.70 kg less BW loss than parity 2 control sows (P < 0.022). Betaine-supplemented sows had greater ADFI in the 6to 11-d, 12to 16-d, and 17to 21-d periods (P < 0.019). Wean-to-estrus intervals (WEI) were 0.31 d shorter (P = 0.004) and had different distribution (P = 0.029) for betaine-supplemented sows than for control sows. Greater percentages, 3.2 and 12.1% of betaine-supplemented sows, returned to estrus on d 3 and 4, respectively, than control sows. In another lactation trial, sows supplemented with 0.21% dietary betaine had 0.51 mm greater follicle diameter (P = 0.043) and 0.23°C lower rectal temperature (P = 0.048) than control sows. The second objective was to develop a cooling pad that efficiently removes excess of heat from lactating sows. Cooling pads were built with an aluminum plate surface, high-density polyethylene base, and copper pipes. Respiration rates and rectal, vaginal, and skin temperatures for 8 replicates of 10 sows were evaluated after 100 min of cooling with different constant cool water flows of 0.00 (4 sows), 0.25 (2 sows), 0.55 (2 sows), or 0.85 L/min (2 sows). The cooling was initiated 1 h after the room reached 35°C. Mean room temperature and relative humidity during the trial were 35.1 ± 0.4°C and 68.4 ± 3.2%, respectively. The 0.55 and 0.85 L/min treatments reduced respiration rates and rectal, vaginal, and skin temperatures after 80 min of cooling (P < 0.001). Respiration rates decreased within 20 to 40 min for sows on the 0.85 L/min treatment (P < 0.001). Overall, heat removal during the trial was 193, 321, and 365 W for the 0.25, 0.55, and 0.85 L/min treatments, respectively (P < 0.001). Betaine supplementation can alleviate some of the heat stress effects in lactating sows. Cooling pads have a greater potential than betaine to reduce heat stress in lactating sows. Initial data indicate that pulsing of cooled water results in more efficient heat transfer per liter of water.