Hernandez-Fonseca et al. (2002), Hoshi (2003) and Merton et al. (2007), respectively, after the transfer of frozen-thawed embryos produced in vitro from slaughterhouse-collected and transvaginally aspirated oocytes. In this study the pregnancy rates were 48.8% for cryopreserved and 55.8% for fresh embryos. A relatively low decrease in viability was found for frozenthawed embryos compared to fresh embryos. The pregnancy rate was improved after the transfer of frozen-thawed embryos derived from oocytes with greater meiotic and developmental competence in comparison with the pregnancy rates after transfer of embryos derived from oocytes with heterogeneous meiotic and developmental competence, as used for embryo production by the authors mentioned above. The results of this study confirm our assumption that the recovery of oocytes in a suitable phase of follicular development can be used to increase the production of fresh and frozen embryos from high performance donors and to improve the pregnancy rate after embryo transfer. In this case, however, the examination of follicular status of selected cows and the timing of oocyte collection for embryo preparation are important. It can be concluded that (a) higher numbers of usable oocytes from infertile, genetically valuable cows can be recovered in the growth phase compared with any other phase of follicular development; (b) greater development of these oocytes results in more embryos for transfer and cryopreservation; (c) the pregnancy rate can be improved after the transfer of frozen-thawed embryos derived from oocytes with greater meiotic and developmental competence.