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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. [ABSTRACT FROM AUTHOR]

Pre-weaned piglets prefer higher temperatures than lactating sows. To address this, swine producers use heating lamps or pads in combination with maintaining farrowing room macroenvironment temperatures at the upper end of the thermoneutral zone (24-25℃) of the lactating sow. This may inadvertently cause thermal stress for lactating sows resulting in decreased feed consumption, and ultimately, reduced milk production and litter growth. Therefore, the objective was to determine the sow level macroenvironment temperature that would improve both sow and litter productivity. In two repetitions, 37 lactating sows (parity = 3.1 ± 1.7) and their litters (d 1 litter size = 12.0 ± 1.0) were housed within 1 of 3 farrowing rooms set to different macroenvironment temperatures: LOW (n = 12 sows and litters; 15.0 ± 0.4℃), MID (n = 13 sows and litters; 19.3 ± 0.2℃), and HIGH (n = 12 sows and litters; 24.6 ± 0.8℃). Lactating sows and their litters were on trial from the onset of farrowing until weaning (19.8 ± 0.9 d of age). Individual farrowing crate temperatures were recorded throughout the trial in 0.14 s intervals using thermocouples mounted at sow head height. Piglets were provided a 0.34 x 1.52 m heating pad with a verified steady state of 35.0℃. Sow body weight (BW) was recorded at 24 h post-farrowing and at weaning, and piglet weights were measured on d 1, 7, 14 and at weaning to determine average daily BW gain (ADG). Liveborn piglet mortality was recorded throughout the trial. Sow feed intake (FI) was recorded daily from d 1 post-farrowing until weaning. The sow was considered the experimental unit for sow level measures and the litter was considered the experimental unit for piglet measures. Data were analyzed using PROC GLIMMIX in SAS 9.4 and using GLM in JMP 15. Regression models were used to determine the optimal macroenvironment temperature to improve sow FI and piglet ADG. Sow FI was greater (P < 0.01) for LOW (7.91 ± 0.38 kg) and MID (7.32 ± 0.37 kg) versus HIGH (6.37 ± 0.39 kg) sows, but similar for LOW and MID sows. Piglet ADG was greater from d 1 to weaning (P < 0.01) for LOW (0.25 ± 0.01 kg) and MID (0.26 ± 0.01 kg) versus HIGH (0.21 ± 0.01 kg) piglets, but similar for LOW and MID piglets. Pre-weaning mortality was similar (P = 0.32; 15.6%) among all treatments. A quadratic effect was observed (P < 0.01) where sow FI was maximized at a macroenvironment temperature of 17.2℃. A cubic effect was observed (P < 0.01) where piglet ADG was greatest at 17.0℃. In summary, these data have implications towards housing lactating sows and their litters at lower macroenvironment temperatures to improve growth performance. [ABSTRACT FROM AUTHOR]

Impacts of heat stress (HS) on lactating sows during the summer causes challenges in production. The study objective evaluated the daily patterns of common HS measures on late lactation sows. Sows in a HS environment, on and off electronic cooling pads (ECP), were compared with sows in a cool room (CR). From a sample of six sows, three sows were assigned to a HS environment, (31℃ daytime for 6 h and 26℃ nighttime for 5 h) with an ECP (n = 1) or without an ECP (nECP, n = 2). Three sows were placed in a CR (n = 3) with set temperature of 20℃. The ECP automatically flushed 2.0 L of cool water (18 to 19℃) when one of the three temperature sensors reached 26℃. Flushing occurred for 30 s replacing 1.73L of water in the ECP. All sows were in farrowing crates and provided ad libitum access to feed and water. Internal Temperature (TI) was measured in 10-minute intervals using vaginal implants. Skin temperature (TS) was measured hourly, using an infrared gun 10 cm behind the ear. Respiration rate (RR) was observed in 30-minute intervals from 0600 to 2200 h over 2 days. Mixed model periodic regressions were performed in R 4.2.2 using REML lme4, fitted to the RR, TS, and TI data. Significant treatment and treatment by periodic regression variables (P < 0.05) indicated the need for separate equations for each treatment. The final model for TI included the random effect of sow, effect of room, and single, double, and triple sine/cosine phase variables for each room. For TI, there were also significant (P < 0.001) interactions of the single-phase sine/cosine variables with the ECP treatment in the HS environment. The final model for TS included the random effect of sow, ECP treatment, single, double, and triple sine/cosine and their interactions with room, and the interaction of the single phase with ECP treatment in the HS environment. The final model for RR included the effects of room and ECP within the HS environment (P < 0.001), the single-phase sine/cosine variables, and their interactions of ECP within the HS environment and CR. Daily increases in RR and TI were much greater for sows in the HS environment compared with the CR, or the sow on the ECP. The RR for the ECP sow increased from 18 to 24 bpm from 6000 h to midafternoon (1500 to 1700 h), versus 65 to 108 bpm for the nECP sows. Overall, the ECP reduced TI on average by 0.39℃ with the greatest impact of 0.8 to 0.9℃ from 1500 to 1900 h. As in previous experiments, the sow on the ECP had greater relative reductions in RR and smaller differences in TI. [ABSTRACT FROM AUTHOR]

Gestating sows become more sensitive to high temperatures at the end of gestation. Cooling pads have been developed that reduce the impact of high environmental temperatures on sows. Some of the added heat stress response may be due to oxidative stress which might be reduced with dietary antioxidants. The objective of this study was to evaluate the daily patterns of common measures of heat stress on late gestation sows with or electronic cooling pads (ECP) with or without the addition of Moringa, a plant with antioxidant activity. Sows (n = 24), 2 days before farrowing, were assigned a 2 × 2 factorial arrangement of treatments: farrowing crates with or without cooling pads and corn-soybean based diets containing either 0 or 4% Moringa leaf powder. Sows were fed 1.36 kg of feed twice a day and had ad-libitum access to water. The farrowing room was targeted to have a 32℃ daytime from 1100 to 1700 h and 26℃ nighttime). The ECP flushed 2.0 L of cool water when one of the three temperature sensors reached 26℃. Skin temperature (TS) was measured hourly using an infrared gun 10 cm behind the ear, and hourly respiration rate (RR) recorded from 600 to 2200 h. Rectal temperatures were (TI) taken at 600, 1300, 1600 and 1900 h. Two statistical analyses were conducted. The first was a mixed model including the fixed effects of ECP, diet, hour of measurement and their interactions with sow included as a random effect. Also, mixed model periodic regressions were fitted to the RR and TS data. The RR was impacted by ECT, hour, and ECP × hour interactions (P < 0.001). The final model for RR included the random effect of sow, main effect of ECP, single phase sine/cosine and 2-phase cosine variables and the interaction with the single-phase variables with ECP treatment (P < 0.001). For TS, there was only a tendency for the ECP treatment (32.4 vs. 33.0℃, P = 0.064) and effect of hour of measurement (P < 0.001) The final model for TS using periodic regression included the random effect of sow, ECP treatment (P = 0.12), single-phase sine and cosine and two-phase sine variables (P < 0.001) and interaction of single-phase sine variable by ECP treatment (P = 0.024). Overall ECP reduced internal temperatures by 0.23℃ (P = 0.17) with trend for a ECP × time interaction (P = 0.074) with the greatest impact at 1300 h (38.04 vs. 37.53, P < 0.02). The ECP produced greater relative reductions in RR and smaller differences in TI. Daily mid- to late-afternoon increases in RR, TS, and TI were reduced for ECP sows. No significant diet or diet by hour interactions were found. [ABSTRACT FROM AUTHOR]

Lactating sows are especially sensitive to heat stress (HS) due to high metabolic demands resulting from milk output. Therefore, there is a need to develop effective cooling technologies that reduce the impact of HS on lactating sows. The study objective was to determine whether electronically controlled cooling pads (ECP) would allow sows to remain euthermic under HS conditions. Twelve multiparous (2.69 ± 0.85) lactating sows (265.4 ± 26.1 kg) and litters (11.4 ± 0.7 piglets/litter) were assigned to either a non-functional ECP (NECP; n = 6) or an ECP (n = 6), housed in farrowing crates, and tested over two repetitions. Sows were provided feed and water ad libitum and all sows were exposed to HS (28.27 ± 1.42°C nighttime to 35.14 ± 0.70°C daytime). Body temperature (TB), was measured hourly using vaginal implants, and respiration rate (RR) was measured in 30 min intervals from 0600 to 2100 hrs over 2 d representing mid- and late lactation. Mixed model periodic regression equations were fitted to the TB and RR to time. The final model for TB included the effect of replicate, random effect of sow, day of lactation as a covariate, single-phase sine and cosine variables for each treatment and 2-phase sine and cosine periodic regression variables. The final model for RR included the random effect of sow, effect of treatment, replicate, day of lactation, sleeping, and single-phase sine and cosine functions for each treatment. An interaction (P < 0.05) between treatment and sine or cosine was observed for TB. For RR there was no interaction for treatment and cosine (P = 0.07), but an interaction (P < 0.05; -9.94) was observed for sine. The significant treatment by wavelength interactions observed indicate a change in RR and TB patterns when sows are placed on ECPs. [ABSTRACT FROM AUTHOR]

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., metabolic heat production) and litter growth performance in HS exposed sows. Over two repetitions, 12 multiparous (2.69 ± 0.85) lactating sows (265.4 ± 26.1 kg) and litters were assigned to either an ECP (n = 6) or a non-functional ECP (NECP; n = 6) and placed into farrowing crates within indirect calorimeters from d 3.7 ± 0.5 to d 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 ± 1.42°C nighttime to 35.14 ± 0.70°C daytime). On d 4, 8, 14, and 18 of lactation, indirect calorimetry was performed on each individual sow and litter to determine total heat production (THP). Body temperature (TB), was measured hourly using vaginal implants, and respiration rate (RR) was measured daily at 0700, 1100, 1300, 1500, and 1900 h. Litter weights were obtained at birth and weaning. An overall decrease (P < 0.01; 25 bpm) in RR and maximum daily TB (P = 0.02; 0.40°C) was observed in ECP versus NECP sows. An increase in THP (P < 0.01; 20.4%) and THP/kg0.75 (P < 0.01; 23.1%) was observed for ECP when compared to NECP sows and litters. Litter growth rate was increased (P < 0.01; 20.8%) in ECP versus NECP sows. In summary, the use of ECP improves litter growth, thermoregulatory measures, and bioenergetic parameters associated with greater milk production in lactating sows exposed to cyclical heat stress. [ABSTRACT FROM AUTHOR]