Cytogenetics of preimplantation embryos sired by bulls heterozygous for the 1/29 translocation

Eighty-eight embryos aged 1 to 15 days sired by bulls heterozygous for the 1/29 chromosome translocation and 28 embryos aged 7 to 15 days sired by a normal bull were chromosomally analysed. All donor females had normal karyotypes. Only 47.4% of the embryos could be karyotyped. Two embryos sired by a heterozygous bull were trisomic. One 2-celled embryo was a 2n/ln mosaic and one 1-celled egg was polyspermic. Both of these were collected from superovulated donors. The mean cell number and mitotic index for 7-day embryos sired by heterozygous bulls were 72 and 3.73%, respectively, and sired by normal bulls, 81 and 5.74%, respectively.