title: Efficiency of different hormonal treatments for estrus synchronization in tropical Santa Inês sheep.
abstract: The aim of this study was to evaluate the effect of (i) the duration of hormone treatment with progestogen sponges during the seasonal anestrus and (ii) the administration of two doses of prostaglandin at 7 days apart during the breeding season on reproductive parameters of Santa Inês ewes. In experiment 1, 32 ewes received intravaginal MAP sponges for 6 (G6 days), 9 (G9 days), or 12 (G12days) days and 75 μg D-cloprostenol i.m. and 300 IU eCG i.m. 1 day before sponge removal. In experiment 2, 23 ewes received two doses of 0.48-mg sodium cloprostenol i.m. 7 days apart. Ovarian follicular dynamic was assessed through transrectal ultrasonography. Blood samples were collected daily to determine progesterone concentrations. In experiment 1, estrus and ovulation rates did not differ (P > 0.05) among protocols and between cyclic and acyclic ewes at the beginning of the experiment. The G9 days treatment showed a lower dispersion of ovulations in relation to onset of estrus when compared to G6 days and G12 days. In experiment 2, all ewes exhibit estrus and ovulated after the second dose of prostaglandin, although ewes that were in diestrus at D0 showed subluteal concentrations of progesterone during the follicle development stage of the treatment. In conclusion, the use of progestogen device during 9 days promotes lower dispersion of ovulation when compared to its use for 6 or 12 days, and the protocol of two doses of prostaglandin 7 days apart synchronizes estrus efficiently but results in follicular development under low progesterone concentrations.
authors.affiliation: Faculty of Veterinary Medicine, Fluminense Federal University, Av. Vital Brasil Filho, 64, CEP 24230-340, Niterói, RJ, Brazil.
authors.forename: Tarcísio Alves
authors.initials: TA
authors.lastname: Texeira
authors.affiliation: Embrapa Goats and Sheep, Núcleo Regional Sudeste, CEJHB-Embrapa Gado de Leite, Rodovia MG133, km42, Cep 36.155-000, Coronel Pacheco, MG, Brazil.
authors.forename: Jeferson Ferreira
authors.initials: JF
authors.lastname: da Fonseca
authors.affiliation: Faculty of Veterinary Medicine, Fluminense Federal University, Av. Vital Brasil Filho, 64, CEP 24230-340, Niterói, RJ, Brazil.
authors.forename: Joanna Maria Gonçalves
authors.initials: JM
authors.lastname: de Souza-Fabjan
authors.affiliation: Faculty of Veterinary Medicine, Fluminense Federal University, Av. Vital Brasil Filho, 64, CEP 24230-340, Niterói, RJ, Brazil.
authors.forename: Luciano
authors.initials: L
authors.lastname: de Rezende Carvalheira
authors.affiliation: Faculty of Veterinary Medicine, Fluminense Federal University, Av. Vital Brasil Filho, 64, CEP 24230-340, Niterói, RJ, Brazil.
authors.forename: Daniel Andrews
authors.initials: DA
authors.lastname: de Moura Fernandes
authors.affiliation: Faculty of Veterinary Medicine, Fluminense Federal University, Av. Vital Brasil Filho, 64, CEP 24230-340, Niterói, RJ, Brazil. fzbr@vm.uff.br.
authors.forename: Felipe Zandonadi
authors.initials: FZ
authors.lastname: Brandão
mesh_terms: D000818:Animals; D001947:Breeding; D003008:Cloprostenol / Q000494:pharmacology; D004973:Estrus Synchronization / Q000187:drug effects*; D005260:Female; D007273:Injections, Intramuscular / Q000662:veterinary; D010060:Ovulation / Q000187:drug effects; D010062:Ovulation Induction / Q000662:veterinary*; D011161:Porifera; D011374:Progesterone / Q000097:blood*; D011372:Progestins / Q000008:administration & dosage / Q000494:pharmacology*; D012621:Seasons; D012756:Sheep / Q000502:physiology*
chemical_list: D011372:Progestins; D003008:Cloprostenol; D011374:Progesterone
keywords: Cyclicity; Native breed; Ovine; Progesterone; Prostaglandin