REPEATED ACUTE ACTIVATION OF THE HYPOTHALAMOPITUITARY-ADRENAL AXIS PRIOR TO AND DURING ESTRUS DID NOT AFFECT REPRODUCTIVE-PERFORMANCE IN GILTS

We investigated the effects of repeated acute activation of the hypoth alamo-pituitary adrenal axis, prior to and during estrus, on reproduct ion in gilts. Individual gilts (n = 24 per treatment) either served as controls or were subjected to daily acute stress (''negative handling ,'' brief electric shock with a battery-operated prodder during confin ement with the experimenter) commencing, on average, 8 days prior to e strus. Gilts subjected to negative handling had a significant elevatio n in plasma concentrations of cortisol that lasted at least 3-4 h, and these gilts were slower than control gilts to approach and interact w ith the experimenter in a standard test. Nevertheless, reproductive pe rformance-as measured by sexual receptivity and proceptivity, ovulatio n, the percentage of gilts that became pregnant, the number of embryos 20-21 days after insemination, and the weight of embryos-was not affe cted by repeated acute activation of the hypothalamo-pituitary adrenal axis. Our results suggest that repeated acute activation of the hypot halamo-pituitary adrenal axis prior to and during estrus does not affe ct the factors that control estrus and ovulation in gilts.