Background: It is uncertain whether long-term cryopreservation affects embryonic development.
Objective: This study was to investigate the effects of long-term cryopreservation on in vitro and in vivo developmental competence of bovine blastocysts.
Methods: The blastocysts were randomly allocated into 3 groups based on the storage time: 0.5-year group, 1-year group and 15-years group. The thawed blastocysts were subjected to in vitro culture or embryo transplantation.
Result: Significantly lower survival rate (89.2%) and re-expansion rate (70.3%) of blastocysts were obtained from 15-years group compared with those of 0.5-year (97.5% and 87.5%) and 1-year (100% and 84.2%) groups (P < 0.05). There were no significant differences in the hatching rate (39.5% to 42.5%) among the three groups and the pregnancy rate between 1-year (35.0%) and 15-years (36.4%) groups.
Conclusions: Although in vitro developmental competence of the 15 years cryopreserved blastocysts was decreased slightly, the pregnancy outcome was not affected.