Effect of Time Interval between Biopsy and Vitrification on Survival of in V/fro-Produced Bovine Blastocysts

The aim of this study was to improve the cryosurvival of bovine blastocysts following biopsy. In vitro-derived bovine blastocysts were biopsied with a metal blade, then cultured for 0 to 20 h in m-SOF and then vitrified in the presence of ethylene glycol and dimethyl sulfoxide. The post-warm survival rates after 24 h of in vitro culturing of the biopsied embryos were significantly higher at 1.25, 2.5, 5 and 10 h than that of 0 and 20 h (69, 73, 78 and 64% vs 34 and 27%, p<0.05, respectively). The survival rate of embryos vitrified at 2.5 and 5 h after biopsy was not different from that of the non-vitrified control group (73 and 78% vs 96%, p=0.08 vs 0.07, respectively). These results indicate that 1.25 to 10 h culture between biopsy and vitrification improves the viability of bovine blastocysts produced in vitro.