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영어

OPU (Ovum pick up) has been an important technique to increase genetic resources for early establishment of genetically important herd and in vitro embryo production system. This study compared relationship between OPU-derived COCs quality and embryo development. The recovery procedures of COCs were performed twice a week using ultrasound guided OPU tools. The 18 gauge disposable needle was connected into 50 mL conical tube by teflon tubing, The grade of COCs was evaluated by microscopic examination. Grade A had 3 or more layers of cumulus cell and compact cytoplasm. Grade B had 1~3 layers of cumulus cell and compact cytoplasm. Grade C had 1 layers cumulus cell and compact cytoplasm. Grade D was denuded oocyte and poor cytoplasm. The collected COCs were fertilized in vitro and developed for 7~8 day in mSOF media. The cleavage rate of grade A/B dominant pick-up group (above 60% of A/B grade rate from total recovered COCs) was 48.9% and that of poor quality was 51.9%. The rate of blastocyst rate in grade A/B dominant OPU procedures after IVF was 28.9%, but poor quality group (below 60% of A/B grade COCs) was 14.8%. The developed blastocysts were transferred into recipient or cryopreserved for further research. When total 11 blastocysts were transferred into surrogate cows with the pregnancy rate (4/11) of 36.3% and 4 calves are expected.