Number of Sperm in the oviducts, Uterus, and Cervix of the Mated Ewe as Affected by Exogenous Estradiol

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Abstract
Six experiments were conducted to determine the ability of exogenous estradiol-17β to increase numbers of sperm in the oviducts, uteri and cervices of inseminated estrous ewes. In a 2 × 3 factorial experiment, ewes were mated during either early or late estrus; ewes in each group were either not treated or were treated with estradiol by subcutaneous injection once, at 6 hr after mating (30 μ of estradiol), or twice, immediately before mating (30 μg) and 6 hr after mating (10 µg). Ewes were necropsied 24 hr after mating, and sperm were recovered from the oviducts, uterus, and anterior, middle, and posterior segments of the cervix. Two estradiol injections, before and after mating, increased sperm numbers significantly (P=.02) in the anterior one-third of the cervix; one estradiol injection, after mating, had no apparent effect. In a 3 × 2 factorial experiment, ewes were in natural unregulated estrus or were in regulated estrus either after induced regression of corpora lutea with prostaglandin F2α or after administration of medroxyprogesterone acetate by intravaginal sponge. Estradiol (30 μg) was injected subcutaneously into one-half of the ewes immediately before mating. Ewes were necropsied 24 hr after mating. Regulation of estrus reduced (P<.05) sperm numbers in the anterior cervix. Estradiol treatment counteracted the effect of regulating estrus. Estradiol did not increase sperm numbers in ewes in natural estrus or increase sperm numbers in any segment of the reproductive tract other than the anterior cervix. In Experiment 3, estradiol was injected intramuscularly into ewes immediately before mating during early estrus; in Experiment 4, estradiol was injected and ewes mated during late estrus; in Experiment 5, estradiol was injected during early estrus and ewes were mated during late estrus; in Experiment 6, ewes were mated during early estrus, and estradiol was injected during late estrus. Ewes were necropsied 2 hr after injection of estradiol or after mating. Control ewes were injected with corn oil in each experiment. Over all four experiments, estradiol treatment increased sperm numbers in the oviducts (P<.01), uterus (P<.005), and anterior and middle segments of the cervix (P<.05 and P<.02, respectively). Estradiol had the greatest effect when administered immediately before mating. Copyright © 1978. American Society of Animal Science . Copyright 1978 by American Society of Animal Science.

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