title: Effect of eCG on the pregnancy rate of ewes transcervically inseminated with frozen-thawed semen outside the breeding season.
abstract: An experiment was conducted to determine whether factors affecting pregnancy rate out-of-season are associated more with transcervical artificial insemination (T-AI) procedures or with the reproductive state of the ewe. Twenty Finncross ewes were treated with progesterone sponges, and at sponge removal (0 h) 10 ewes were treated with eCG. Blood samples were collected for LH and progesterone analyses, and follicular development was monitored using ultrasonography. Ewes were inseminated from 48 to 52 h with 200 million motile frozen-thawed spermatozoa. The incidence of estrus, LH surges and ovulation was greater (P < 0.01) and intervals to these responses were shorter (P < 0.01) in the eCG-treated ewes. The number of follicles > 5 mm was higher (P < 0.05) in eCG-treated than control ewes. Progesterone concentrations increased and remained elevated through Day 19 in 7 eCG-treated and in 1 control ewe, and these ewes were pregnant based upon ultrasonographic examination. The results demonstrate that the T-AI technique using frozen-thawed semen produces a relatively high (70%) pregnancy rate out-of-season. The pregnancy rate was found to reflect primarily the reproductive condition of the ewe.
authors.affiliation: Department of Animal Science, University of Minnesota, St. Paul 55108, USA.
authors.forename: M Q
authors.initials: MQ
authors.lastname: Husein
authors.forename: M T
authors.initials: MT
authors.lastname: Bailey
authors.forename: M M
authors.initials: MM
authors.lastname: Ababneh
authors.forename: J E
authors.initials: JE
authors.lastname: Romano
authors.forename: B G
authors.initials: BG
authors.lastname: Crabo
authors.forename: J E
authors.initials: JE
authors.lastname: Wheaton
mesh_terms: D000818:Animals; D006063:Chorionic Gonadotropin / Q000494:pharmacology*; D015925:Cryopreservation; D004971:Estrus / Q000187:drug effects / Q000502:physiology; D005260:Female; D007315:Insemination, Artificial / Q000379:methods / Q000662:veterinary*; D007986:Luteinizing Hormone / Q000097:blood; D008297:Male; D006080:Ovarian Follicle / Q000000981:diagnostic imaging / Q000187:drug effects / Q000502:physiology; D010062:Ovulation Induction / Q000379:methods / Q000662:veterinary; D011247:Pregnancy; D011270:Pregnancy, Animal / Q000187:drug effects*; D011374:Progesterone / Q000097:blood / Q000494:pharmacology; D012621:Seasons; D012662:Semen Preservation; D012756:Sheep; D013081:Sperm Motility; D014463:Ultrasonography
chemical_list: D006063:Chorionic Gonadotropin; D011374:Progesterone; D007986:Luteinizing Hormone