Monosomy and trisomy in bovine embryos sired by bulls heterozygous for the 1 29 Robertsonian translocation chromosome

Mature cows (n = 37) were superovulated and inseminated with semen from either bulls heterozygous for the 1 29 Robertsonian translocation or bulls with a normal karyotype. A total of 163 embryos was recovered, and preparations suitable for cytogenetic analysis were obtained from 67 (41.1%) of these. The karyotype was unbalanced in three (4.5%) of the embryos sired by semen from a bull carrying the translocation, whereas no karyotypic imbalance was recognized in the control group of embryos. Two of the unbalanced embryos were monosomic, while the third embryo was trisomic.