Structural Changes Associated with Freezing of Bovine Embryos

Abstract

The structural changes associated with freezing and thawing were examined in bovine embryos at three developmental stages: Day 5, Day 7, and Day 13 (Day 0 = day of estrus). Embryos collected at Day 5 had 8–16 cells, and contained numerous vesicles and primitive junctional regions between some adjacent blastomeres. After cooling to 4°C, the distribution of organelles within blastomeres as well as the spacial arrangement of blastomeres was disrupted.