| Autor: |
Arrais AM; Departamento de Reprodução e Avaliação Animal, Universidade Federal Rural do Rio de Janeiro, Seropédica, Brazil., Mello MRB; Departamento de Reprodução e Avaliação Animal, Universidade Federal Rural do Rio de Janeiro, Seropédica, Brazil., Vergani GB; Faculdade de Ciências Agrárias e Veterinárias, Universidade Estadual Paulista, Jaboticabal, Brazil., Figueira LM; Faculdade de Veterinária, Universidade Federal Fluminense, Niterói, Brazil., Esteves SN; Embrapa Pecuária Sudeste, São Carlos, Brazil., Pereira VSDA; Embrapa Pecuária Sudeste, São Carlos, Brazil., Bartlewski PM; Department of Biomedical Sciences, Ontario Veterinary College, University of Guelph, Guelph, Canada., Oliveira MEF; Faculdade de Ciências Agrárias e Veterinárias, Universidade Estadual Paulista, Jaboticabal, Brazil., Souza-Fabjan JMG; Faculdade de Veterinária, Universidade Federal Fluminense, Niterói, Brazil., Fonseca JFD; Embrapa Caprinos e Ovinos, Coronel Pacheco, Brazil. |
| Abstrakt: |
This study assessed the feasibility of in vivo embryo production and nonsurgical embryo recovery (NSER) in Morada Nova ewes (an endangered native Brazilian breed of sheep) subjected to different estrus synchronization and/or superovulation protocols. Ewes received intravaginal sponges soaked with 60 mg medroxyprogesterone acetate (MAP), which were kept in place for six (G6; n = 12), nine (G9; n = 12), or 12 (G12; n = 12) days. Half of the ewes in each group remained estrus synchronized only ( SYNCH ) and the other half was superovulated ( SOV ) with 133 mg porcine follicle-stimulating hormone (pFSH). There were no differences ( p > 0.05) in antral follicle counts determined with ultrasonography 60 hours before MAP sponge removal (or at the time of the first pFSH dose) among G6 (6.4 ± 0.9), G9 (6.2 ± 0.7), and G12 (5.5 ± 0.6). Estrus responses and NSER success rates did not vary ( p > 0.05) among the three progestin-treatment groups of ewes for either estrus-induced or superovulated animals. The onset of estrus occurred 10-12 hours later ( p < 0.01) in G9 SYNCH ewes compared with G6 SYNCH and G12 SYNCH, and the duration of estrus was ∼19 hours greater ( p < 0.01) in G9 SOV than in G6 SOV . The average duration of the NSER procedure was 32.6 ± 1.3 minutes. At least one structure was recovered in 85.7% of synchronized and in 87.5% of superovulated ewes. Viable embryo recovery rates were also similar ( p > 0.05) for G6 (1.0 ± 0.3 and 2.5 ± 1.5), G9 (1.3 ± 0.5 and 4.8 ± 2.0), and G12 groups (1.0 ± 0.3 and 4.8 ± 2.3; estrus-synchronized and superovulated ewes, respectively). In conclusion, progestogen pretreatment of different durations and NSER can be employed in Morada Nova ewes, resulting in reasonable viable embryo recovery rates in both estrus-synchronized and superovulated animals. Therefore, both techniques are suitable for use in commercial settings as well as small ruminant conservation programs. |
