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Effect of season and gonadotrophin preparation on superovulatory response and embryo quality of Portuguese Black Merino ewes

Ano
2008
Documento
Abstract

The aim of the present work was to assess the effects of season (spring or fall) and of stimulation with either ovine FSH (Ovagen®) or porcine pituitary extract (Pluset®) on the superovulatory response and embryo quality of Portuguese Black Merino sheep. Ewes were synchronized with intravaginal sponges containing fluorogestone acetate (Chronogest®, Intervet Laboratories) and subjected to laparoscopic intrauterine insemination and natural mating. Ovary examination and embryo recovery were carried out by laparotomy at day 7 after sponge removal and data recorded for number of corpora lutea (OR), unfertilized oocytes (UO), empty zona pellucida (ZP), total embryos (TEMB) and total freezable embryos (FEMB). Fertilization (FR= TEMB/TEMB+UO) and freezabilty (FRR= FEMB/TEMB) rates, efficacy of ova recovery rate RR = (TEMB + UO + ZP) / nº of CL and embryo recovery rate ERR = (TEMB / nº of CL) were calculated. No differences (p<0.05) were observed in OR, TEMB or FEMB between seasons. Higher (p<0.05) RR and ERR (p<0.01) were obtained in spring, but FRR was higher (p<0.05) in the fall. No differences (p<0.05) were found for OR and for the percentage of superovulatory response (=4 CL) for ewes stimulated in spring with either Ovagen® or Pluset® but TEMB, RR and ERR were higher (p<0.05) in Ovagen® treated ewes. It is concluded that ovary stimulation and embryo transfer can be successfully applied to this endangered sheep breed during both fall and spring and that the type of gonadotrophin utilized can have a significant impact in the results obtained

Keywords

Sheep; Superovulation; Black Merino; Season; Embryos

Tipo de Artigo
Investigação
Tipo de Revisão
Internacional
Âmbito Geográfico
Internacional
Situação
Publicado
Área de Trabalho
Referência

Bettencourt, E; Bettencourt, C; Chagas e Silva, N; Ferreira, P; Manito, C; Matos, C; Romão, R; Rocha, A (2008). Effect of season and gonadotrophin preparation on superovulatory response and embryo quality of Portuguese Black Merino ewes. Small Ruminant Research, 74: 134-139