In vitro development of the reconstructed bovine embryos activated at various time after electrofusion

The dynamics of in vitro development of reconstructed bovine embryos activated at various time after electrofusion was studied. The in vitro mature oocytes without zona pellucida enucleated using the blind method were taken as cytoplasts. Fetal fibroblasts were used as the nuclei source. Approximately 40% of embryos activated between 3 and 3.2 hours after electrofusion developed to blastocysts. The efficiency of in vitro development of cloned embryo of cloned embryo did not decrease when the time between electrofusion and activation was extended up to 4–5 hours. The pattern of more successful development of in vitro reconstructed embryos was found using enucleated oocytes, extrusion the first polar body to 18 hours in comparison with oocytes matured in vitro afterwards, as cytoplasts.