Developmental kinetics of in vitro–produced bovine embryos: An aid for making decisions

Embryo developmental kinetics and embryo survival after cryopreservation have been correlated with embryo quality and viability. The main objectives of this work were to analyze developmental ability and quality of in vitro–produced bovine embryos in relation to their kinetics and to establish a criterion of quality to predict further viability. Embryos were classified and grouped by their specific stage of development (2, 3–4, or ≥ 5 cells) at 44 hours post insemination (hpi) and cultured separately up to Day 8. On Days 7 and 8, good quality expanded blastocysts were vitrified or frozen. Cryopreserved surviving hatched embryos were stained for cell counts. Embryos at a more advanced stage (3–4 cells, and ≥5 cells) developed to morulae (P