engleski

Superovulatory response of Lesvos ewes to p-FSH

Establishing superovulation protocols is essential for the quick improvement of indigenous sheep breeds through MOET programs. Lesvos ewes received FGA (20 mg) sponges for 12 days. Superovulation was induced with 200 mg p-FSH, in either 8 (SOV1, n = 18) or 6 (SOV2, n = 18) decreasing doses and 200 IU eCG at sponge removal (SR), followed by 8 lg GnRH 24 h after SR and were repeatedly mated to Lesvos rams. Embryos were collected 7 days post estrus, after slaughter. Transrectal ovarian ultrasonography (TROVU) was performed in 12 ewes, every 24 h, starting before the 1st FSH dose, ending 24 h after GnRH. Serum P4 and E2 concentrations were determined from sponge insertion to slaughter, using a radioimmunoassay. Data was analysed by t-test and regression. TROVU findings, P4 and E2 concentrations revealed no difference in the ovarian status between groups at the beginning of treatment. High ovarian response without overstimulation or premature luteal regression was observed. In SOV2 group more CL (18.4±9.4) and embryos (7.9±6.3) were recorded than in SOV1 group (16.6±7.7 and 5.0±5.7, respectively), yet the difference was not significant. TROVU 24 h after SR gave a realistic picture of the superovulatory response. Successful superovulation of Lesvos ewes is presented for the first time ; the 6-doses protocol would be recommended based on better results (CL, embryos), less labor required and less stress for the animals. (Financed by SEE-ERA.NET Plus, ERA 83.)

superovulation; pFSH; ewes; Lesvos breed; ovarian response; MOET programs; transrectal ovarian ultrasonography

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