Influence of estradiol-17 beta on fertility in confined sheep inseminated with frozen semen.
Impaired sperm transport is believed to be a major cause of reduced fertiity in ewes inseminated with frozen semen. Because of suggestions that estradiol improves sperm transport, estradiol-17 beta was given to mature ewes at progestagen-induced estrus to test effects on fertility after artificial insemination with frozen semen. Conception rates, based on progesterone determinations made 18 days after insemination, were 43% for ewes injected with 50 microgram estradiol-17 beta and inseminated with frozen semsn, 52% for ewes inseminated with frozen semen but given no estradiol and 86% for ewes inseminated with fresh semen. Lambing rates were 6, 35 and 69%, respectively. The markedly greater difference between conception rates and lambing rates for the estradiol-treated ewes suggests that estradiol caused a substantial increase in the early embryonic mortality associated with the use of frozen semen.
D000818:Animals; D004958:Estradiol / Q000494:pharmacology*; D004971:Estrus; D005260:Female; D005298:Fertility / Q000187:drug effects*; D007315:Insemination, Artificial / Q000662:veterinary*; D008297:Male; D011247:Pregnancy; D011374:Progesterone / Q000097:blood; D011372:Progestins; D012662:Semen Preservation / Q000662:veterinary; D012756:Sheep
D011372:Progestins; D011374:Progesterone; D004958:Estradiol