Effect of Drip Cooling on Sow Body Weight and Litter Performance During Summer

Abstract During lactation, maximizing sow feed intake is critical to sustaining sow body weight and milk production for litter growth. However, heat stress can reduce the lactation feed intake of sows during summer. Drip cooling has shown positive effects on reducing the heat stress of pigs, but there are limited data on the effect of drip cooling on lactating sows. Therefore, the objective of this experiment was to evaluate the effect of drip cooling on lactating sow farrowing performance and litter growth in a hot and humid environment. A total of 300 sows (Line 3, PIC, Hendersonville, TN) were used in this experiment. Five 60-stall farrowing rooms (15 stalls per row and 4 rows per room) were used with tunnel ventilation and evaporative cool cells. At approximately d 110 to 112 of gestation, sows were blocked by body condition score (BCS), parity, and offspring sire (Line 2 or Line 3 sires), then randomly allotted to farrowing stalls with or without drip cooling. Water drippers were located above the stall and aimed at the shoulder region of the sow. The set point of the drip cooling system started at 24°C, and the system ran on a 10-min cycle (2 min on and 8 min off). Evaporative cooling cells started circulating water at 26°C and were used in all farrowing rooms. Drippers were disabled in 3 of every 6 farrowing stalls to balance the environmental effects. The first and third rows of the farrowing rooms started with the first three stalls without drip cooling, while the second and fourth rows started with the first three stalls with drip cooling. After farrowing, sows had ad libitum access to lactation feed. Only piglets from sows bred to Line 2 boars (219 litters) were recorded for litter performance data. Line 3 piglets were not included in litter performance data, but sows of these piglets were included in sow BW and feed disappearance data. Sows with drip cooling had greater (P < 0.05) feed disappearance and litter growth performance, and reduced (P < 0.05) BW change, but also had a marginal difference of decreased (P < 0.10) percentage bred back by d 30 after weaning (Table 1). In conclusion, drip cooling improved sow and litter performance in barns with tunnel ventilation and evaporative cool cells during summer.