Effects of space allocation and temperature on periparturient maternal behaviors, steroid concentrations, and piglet growth rates.

Preparturient sows were randomly assigned to either a farrowing crate (n = 12) or farrowing pen (n = 12) across cool and hot seasons (with or without drip cooling) to study space allocation and temperature effects on periparturient maternal behaviors, steroid concentrations, and piglet growth rates. Concentrations of estradiol-17 beta (E2 beta), progesterone (P4), and cortisol were quantified in blood collected from surgically implanted vena cava cannulas. Sows were videotaped from 2 h before to 2 h after farrowing. Similar periparturient behaviors were displayed by all sows, regardless of farrowing environment. Sows in pens had lower (P < .05) prepartum P4 concentrations from d -6 to the day preceding farrowing and a reduced (P < .05) piglet birth interval compared with sows in crates (12.95 +/- 1.35 min vs 18.31 +/- 2.21 min, respectively). Additionally, compared with multiparous sows in crates, multiparous sows in pens weaned heavier piglets (P < .05). Estradiol-17 beta concentrations were lower (P < .01) throughout lactation during hot weather for sows with or without drip cooling, averaging 9.30 pg/mL and 8.57 pg/mL, respectively, compared with 18.65 pg/mL for sows during cool weather. This decrease in E2 beta concentration in sows during hot weather was correlated with an extended (P < .05) interval from weaning to first estrus for the sows in hot weather compared to sows during cool weather. Cortisol concentrations decreased progressively during lactation and were not associated with litter weight gains or the interval between weaning and first estrus.