title: Effects of preovulatory estradiol on embryo survival and pregnancy establishment in beef cows.
abstract: The role of preovulatory estradiol on post-fertilization embryo survival and pregnancy establishment has not been well characterized in beef cows. We hypothesized that preovulatory estradiol is important for embryo survival and pregnancy establishment in beef cows. Twenty-four ovariectomized multiparous cows were used in a replicated 3×3 Latin Square design. Cows received estradiol cypionate (ECP) 36h, estradiol benzoate (EB) 12h, or no estradiol (CON) before a gonadotropin-releasing hormone (d 0) induced LH surge. Luteal phase progesterone was mimicked with twice daily progesterone injections from d 3 to 6. On d 7 cows received one embryo and progesterone was supplemented with progesterone-releasing devices (CIDR). Expression of interferon stimulated genes, ISG15, MX2, and OAS1, in leukocytes was determined on d 17, 19, 21, and 28 to determine capability of embryonic signaling. Pregnancy specific protein B concentrations were measured in serum samples from d 17 through 29 to determine embryonic attachment. Transrectal ultrasonography was performed on d 29 and 32 to determine pregnancy viability (heartbeat). Serum estradiol profiles during simulated proestrus/estrus were different (P<0.001) between treatments. Mean serum progesterone concentrations from d 17 to 24 were decreased (P=0.05) in EB and ECP cows compared to CON. Transrectal ultrasonography indicated that fewer CON (4%) cows had a viable embryo present compared to estradiol treated cows (25%). Embryonic loss in cows that did not receive estradiol during the simulated preovulatory period occurred following maternal recognition of pregnancy, indicating that its impact was likely on uterine receptivity and embryonic attachment.
authors.affiliation: Department of Animal Sciences, South Dakota State University, Brookings, SD, USA; United States Department of Agriculture - Agricultural Research Service, Fort Keogh, Miles City, MT, USA.
authors.forename: Crystal A
authors.initials: CA
authors.lastname: Madsen
authors.affiliation: Department of Animal Sciences, South Dakota State University, Brookings, SD, USA. Electronic address: George.Perry@sdstate.edu.
authors.forename: George A
authors.initials: GA
authors.lastname: Perry
authors.affiliation: Department of Animal Sciences, South Dakota State University, Brookings, SD, USA.
authors.forename: Christina L
authors.initials: CL
authors.lastname: Mogck
authors.affiliation: Department of Veterinary and Biomedical Sciences, South Dakota State University, Brookings, SD, USA.
authors.forename: Russell F
authors.initials: RF
authors.lastname: Daly
authors.affiliation: United States Department of Agriculture - Agricultural Research Service, Fort Keogh, Miles City, MT, USA.
authors.forename: Michael D
authors.initials: MD
authors.lastname: MacNeil
authors.affiliation: United States Department of Agriculture - Agricultural Research Service, Fort Keogh, Miles City, MT, USA. Electronic address: tom.geary@ars.usda.gov.
authors.forename: Thomas W
authors.initials: TW
authors.lastname: Geary
mesh_terms: D000818:Animals; D002417:Cattle / Q000196:embryology* / Q000502:physiology*; D004958:Estradiol / Q000008:administration & dosage / Q000031:analogs & derivatives* / Q000097:blood* / Q000494:pharmacology; D005260:Female; D005498:Follicular Phase; D005786:Gene Expression Regulation / Q000502:physiology; D011247:Pregnancy; D011257:Pregnancy Proteins / Q000235:genetics / Q000378:metabolism
chemical_list: D011257:Pregnancy Proteins; C074283:estradiol 3-benzoate; D004958:Estradiol; C007630:estradiol 17 beta-cypionate
keywords: Embryo survival; Estradiol; Pregnancy establishment