Dose-response shift in the ability of gilts to remain pregnant following exogenous estradiol-17 beta exposure.
Sixty mated gilts were assigned to a 2 X 6 factorial arrangement (n = 5) of day of injection (d 9 and 10 vs 12 and 13; d 0 = first day of estrus) and dose of estradiol-17 beta (0, .125, .5, 2, 8 and 32 mg X gilt-1 X d-1). Gilts were subsequently slaughtered on d 30; pregnancy was verified and percent embryonic survival calculated. A 64-fold shift in the dose-response curve for percent embryonic survival illustrated that the adverse effects of exogenous estradiol-17 beta were less when administered on d 12 and 13 as compared with d 9 and 10 (day X dose, P less than .01). This experiment demonstrated that the uterine-embryonic environment of d 12 and 13 pregnant gilts was more tolerant of exogenous estrogen alterations than that of d 9 and 10 pregnant gilts.
D000818:Animals; D001755:Blastocyst / Q000502:physiology; D004305:Dose-Response Relationship, Drug; D004958:Estradiol / Q000494:pharmacology*; D005260:Female; D005865:Gestational Age; D011247:Pregnancy; D011270:Pregnancy, Animal / Q000187:drug effects*; D013552:Swine / Q000502:physiology*
D004958:Estradiol