The incidence of polyploidy and mixoploidy in early bovine embryos derived from in vitro fertilization

The present work describes a cytogenetic study of early bovine embryos (two to sixteen blastomeres) produced in vitro to determine the proportion of embryos carrying chromosome abnormalities. The embryos were produced from follicular oocytes matured in vitro and fertilized by sperm prepared using the 'swim up' method. Slides were prepared according to an 'air drying' method and the chromosomal complement of embryos was studied by Giemsa-staining. Approximately 45% of embryo preparations were suitable for analysis. The results revealed that 23% of cytogenetically analysed embryos were chromosomally abnormal. The abnormalities observed included triploidy (6.9%), tetraploidy (4.0%), mixoploidy (7.9%) and haploidy (4.5%). The results of this study were compared to the results of other studies with several species.