title: Efficiency of superstimulatory protocol P-36 associated with the administration of eCG and LH in Nelore cows.
abstract: Recent work with P-36 demonstrates that the replacement of the last two doses of Follicle-Stimulating Hormone (FSH) with equine chorionic gonadotropin (eCG) increases embryo yields. However, it is unclear if the positive effect of eCG is related to its FSH-like activity, LH-like activity, or both. This study aimed to verify the replacement of eCG with pLH on the last day of superstimulatory treatment. Twenty-five Nelore cows were allocated to four groups: P-36 (control), P-36/eCG, P-36/LH2, and P-36/LH4. All animals underwent four treatments in a crossover design. The control group cows were superstimulated with decreasing doses of porcine Follicle-Stimulating Hormone (pFSH, 133 mg, im). In the P-36/eCG, P-36/LH2, and P-36/LH4 groups, the last two doses of pFSH were replaced in the former group by two doses of eCG (200 IU each dose, im) and in the latter two groups by two doses of pLH (1 and 2 mg each dose, im), respectively. Donors received fixed-time artificial insemination 12 and 24 hours after pLH. Embryo flushing was performed on D16. Data were analyzed by ANOVA (Proc Mixed, SAS). There was a trend of decreasing ovulation rate when comparing groups LH2 and eCG (P = 0.06). However, there was no significant difference in the mean number of viable embryos among groups P-36 (3.3 ± 0.7), P-36/eCG (4.5 ± 0.5), P-36/LH2 (3.7 ± 0.8), and P-36/LH4 (4.2 ± 1.0). It is concluded that the replacement of eCG by pLH on the last day of superstimulatory treatment can be performed with no significant variation in the production of viable embryos.
authors.affiliation: Department of Veterinary Medicine, Integrated College Campo Mourao, Parana, Brazil.
authors.forename: A C S
authors.initials: AC
authors.lastname: Oliveira
authors.affiliation: Department of Animal Science, University of Sao Paulo, Piracicaba, Sao Paulo, Brazil.
authors.forename: M C C
authors.initials: MC
authors.lastname: Mattos
authors.affiliation: Department of Animal Science, University of Sao Paulo, Piracicaba, Sao Paulo, Brazil.
authors.forename: M R
authors.initials: MR
authors.lastname: Bastos
authors.affiliation: Department of Biostatistics, University of Sao Paulo State, Botucatu, Sao Paulo, Brazil.
authors.forename: L A
authors.initials: LA
authors.lastname: Trinca
authors.affiliation: Department of Pharmacology, University of Sao Paulo State, Botucatu, Sao Paulo, Brazil.
authors.forename: E M
authors.initials: EM
authors.lastname: Razza
authors.affiliation: Department of Pharmacology, University of Sao Paulo State, Botucatu, Sao Paulo, Brazil.
authors.forename: R A
authors.initials: RA
authors.lastname: Satrapa
authors.affiliation: Department of Animal Science, University of Sao Paulo, Piracicaba, Sao Paulo, Brazil.
authors.forename: R
authors.initials: R
authors.lastname: Sartori
authors.affiliation: Department of Pharmacology, University of Sao Paulo State, Botucatu, Sao Paulo, Brazil. Electronic address: cmbarros@ibb.unesp.br.
authors.forename: Ciro M
authors.initials: CM
authors.lastname: Barros
mesh_terms: D000818:Animals; D002417:Cattle / Q000502:physiology*; D006063:Chorionic Gonadotropin / Q000008:administration & dosage / Q000494:pharmacology*; D003008:Cloprostenol / Q000008:administration & dosage / Q000494:pharmacology; D004958:Estradiol / Q000008:administration & dosage / Q000494:pharmacology; D004973:Estrus Synchronization / Q000187:drug effects / Q000379:methods; D005260:Female; D005640:Follicle Stimulating Hormone / Q000008:administration & dosage / Q000494:pharmacology; D007315:Insemination, Artificial / Q000662:veterinary; D007986:Luteinizing Hormone / Q000008:administration & dosage / Q000494:pharmacology*; D011374:Progesterone / Q000008:administration & dosage / Q000494:pharmacology; D013480:Superovulation / Q000187:drug effects*
chemical_list: D006063:Chorionic Gonadotropin; D003008:Cloprostenol; D011374:Progesterone; D004958:Estradiol; D007986:Luteinizing Hormone; D005640:Follicle Stimulating Hormone
keywords: Embryo transfer; Equine chorionic gonadotropin; LH; Nelore; Superstimulation