Repeated acute activation of the hypothalamo-pituitary adrenal axis prior to and during estrus did not affect reproductive performance in gilts.
We investigated the effects of repeated acute activation of the hypothalamo-pituitary adrenal axis, prior to and during estrus, on reproduction 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 confinement with the experimenter) commencing, on average, 8 days prior to estrus. Gilts subjected to negative handling had a significant elevation in plasma concentrations of cortisol that lasted at least 3-4 h, and these gilts were slower than control gilts to approach and interact with the experimenter in a standard test. Nevertheless, reproductive performance--as measured by sexual receptivity and proceptivity, ovulation, the percentage of gilts that became pregnant, the number of embryos 20-21 days after insemination, and the weight of embryos--was not affected by repeated acute activation of the hypothalamo-pituitary adrenal axis. Our results suggest that repeated acute activation of the hypothalamo-pituitary adrenal axis prior to and during estrus does not affect the factors that control estrus and ovulation in gilts.
Turner
A I
AI
Department of Physiology, Monash University, Clayton, Victoria, Australia.
Hemsworth
P H
PH
Hughes
P E
PE
Tilbrook
A J
AJ
D000311:Adrenal Glands / Q000502:physiology*; D000818:Animals; D004597:Electroshock; D004971:Estrus / Q000502:physiology*; D005260:Female; D005306:Fertilization; D006854:Hydrocortisone / Q000097:blood; D007030:Hypothalamo-Hypophyseal System / Q000502:physiology*; D008297:Male; D010060:Ovulation / Q000502:physiology; D011247:Pregnancy; D012098:Reproduction / Q000502:physiology*; D012726:Sexual Behavior, Animal / Q000502:physiology; D013552:Swine / Q000502:physiology*
D006854:Hydrocortisone