Heat stress (HS) decreases lactation output in sows due to an attempt to reduce metabolic heat production. However, this negatively affects litter growth performance. Therefore, the study objective was to determine whether electronically controlled cooling pads (ECP) would improve indirect measures of lactation output (e.g., total heat production [THP]) and litter growth performance in HS exposed sows. Over two repetitions, 12 multiparous (2.69 ± 0.85) lactating sows (265.4 ± 26.1 kg body weight [BW]) and litters were assigned to either an ECP (n = 3/repetition) or a non-functional ECP (NECP; n = 3/repetition) and placed into farrowing crates within indirect calorimeters from days 3.7 ± 0.5 to 18.7 ± 0.5 of lactation. Litters were standardized across all sows (11.4 ± 0.7 piglets/litter), and sows were provided ad libitum feed and water. All sows were exposed to cyclical HS (28.27 ± 0.26 °C nighttime to 33.09 ± 0.19°C daytime). On days 4, 8, 14, and 18 of lactation, indirect calorimetry was performed on each individual sow and litter to determine THP and THP/kg BW0.75. Body temperature (TB) was measured hourly using vaginal implants, and respiration rate (RR; breaths per minute [bpm]) was measured daily at 0700, 1100, 1300, 1500, and 1900 h. Sow feed intake (FI) was assessed daily. Litter weights were obtained at birth, on days 4, 8, 14, and 18 of lactation, and at weaning. Data were analyzed using PROC GLIMMIX with sow and/or litter as the experimental unit. An overall decrease (P < 0.01; 25 bpm) in RR and maximum daily TB (P = 0.02; 0.40 °C) was observed in ECP vs. NECP sows. An increase in THP (P < 0.01; 20.4%) and THP/kg BW0.75 (P < 0.01; 23.1%) was observed for ECP when compared with NECP sows and litters. Litter average daily gain and weaning weight were increased (P < 0.05; 25.0 and 19.2%, respectively) for ECP vs. NECP litters. No FI differences were observed (P = 0.40) when comparing ECP (5.66 ± 0.31 kg/d) and NECP (5.28 ± 0.31 kg/d) sows. In summary, ECPs improve litter growth, thermoregulatory measures, and bioenergetic parameters associated with greater milk production in lactating sows exposed to cyclical HS.

中文翻译：

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电控降温垫可以改善热应激泌乳母猪的窝生长性能和产奶量的间接措施

热应激 (HS) 会降低母猪的泌乳量，因为它试图减少代谢热的产生。然而，这会对窝的生长性能产生负面影响。因此，该研究的目的是确定电控降温垫 (ECP) 是否会改善接触 HS 的母猪的泌乳量（例如，总产热量 [THP]）和窝仔猪生长性能的间接测量值。在两次重复中，12 头经产 (2.69 ± 0.85) 哺乳母猪（265.4 ± 26.1 kg 体重 [BW]）和窝被分配到 ECP（n = 3/重复）或非功能性 ECP（NECP；n = 3/重复）并从哺乳期第 3.7 ± 0.5 天到 18.7 ± 0.5 天放置在间接量热计内的分娩栏中。所有母猪的窝数均已标准化（11.4 ± 0.7 头仔猪/窝），母猪可随意采食和饮水。所有母猪都暴露于周期性 HS（28.27 ± 0.26 °C 夜间至 33.09 ± 0.19 °C 白天）。在泌乳的第 4、8、14 和 18 天，对每头母猪和每窝仔猪进行间接量热法以确定 THP 和 THP/kg BW0.75。使用阴道植入物每小时测量一次体温 (TB)，每天在 0700、1100、1300、1500 和 1900 时测量呼吸率（RR；每分钟呼吸次数 [bpm]）。每天评估母猪采食量 (FI)。在出生时、哺乳期第 4、8、14 和 18 天以及断奶时获得窝重。使用 PROC GLIMMIX 以母猪和/或窝作为实验单位分析数据。在 ECP 与 NECP 母猪中观察到 RR 和最大每日结核病（P = 0.02；0.40 °C）总体下降（P < 0.01；25 bpm）。THP (P < 0.01; 20.4%) 和 THP/kg BW0.75 (P < 0.01; 23. 与 NECP 母猪和窝仔猪相比，观察到 ECP 为 1%。ECP 与 NECP 窝相比，窝平均日增重和断奶重增加（分别为 P < 0.05；25.0 和 19.2%）。比较 ECP (5.66 ± 0.31 kg/d) 和 NECP (5.28 ± 0.31 kg/d) 母猪时，未观察到 FI 差异 (P = 0.40)。总而言之，ECP 改善了仔猪生长、体温调节措施和生物能量参数，这些参数与暴露于周期性 HS 的泌乳母猪的产奶量增加有关。