EN
The studies were performed on 890 oocytes collected from 67 ovaries. For cultivation in vitro 302 oocytes were qualified. Cytogenetic slides were made from 236 oocytes cultivated in vitro. Out of them only 103 oocytes (44%) proved to be suitable for cytogenetic analysis. It was found that: 28% of the oocytes were at metaphase I, 4% at anaphase I, 14% at telophase I and 54% at metaphase II of meiosis. Among secondary oocytes which were studied cytogenetically (metaphase II) 8% of the cells had diploid number of chromosomes. The studies showed that cytogenetic analysis could be useful to assess the maturation progress of oocytes in vitro and to study chromosome abnormalities.