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 o r without drip cooling) to study space allocation and temperature effe cts on periparturient maternal behaviors, steroid concentrations, and piglet growth rates. Concentrations of estradiol-17 beta (E(2) beta), progesterone (P-4), and cortisol were quantified in blood collected fr om surgically implanted vena cava cannulas. Sows were videotaped from 2 h before to 2 h after farrowing. Similar periparturient behaviors we re displayed by all sows, regardless of farrowing environment. Sows in pens had lower (P < .05) prepartum P-4 concentrations from d -6 to th e day preceding farrowing and a reduced (P < .05) piglet birth interva l compared with sows in crates (12.95 +/- 1.35 min vs 18.31 +/- 2.21 m in, respectively). Additionally, compared with multiparous sows in cra tes, multiparous sows in pens weaned heavier piglets (P < .05). Estrad iol-17 beta concentrations were lower (P < .01) throughout lactation d uring hot weather for sows with or without drip cooling, averaging 9.3 0 pg/mL and 8.57 pg/mL, respectively, compared with 18.65 pg/mL for so ws during cool weather. This decrease in E(2) beta concentration in so ws during hot weather was correlated with an extended (P < .05) interv al from weaning to first estrus for the sows in hot weather compared t o sows during cool weather. Cortisol concentrations decreased progress ively during lactation and were not associated with litter weight gain s or the interval between weaning and first estrus.