A mola hydatidosa coexistent with a foetus in a bovine freemartin pregnancy.

Molar transformations of the bovine placenta are extremly rare phenomenona and the aetiology of this genuine placental disease is still unknown. In the present study, an uncommon case of a German Holstein Friesian foetus co-twinned with a hydatidiform mole is described. Cytogenetic and fluorescence in situ hybridization analysis of cell cultures as well as prove of the presence of the SRY gene sequence revealed a heterosexual twin pregnancy. A chimeric condition of the mole was also established. In addition, an XO cell population was detected in the co-twin as well as in the mole. Upon examination of microsatellites of the parents, the mole and the co-twin an androgenetic origin of the mole is suggested, supporting the hypothesis that molar transformation of the bovine placenta may be caused by an androgenetic origin. Furthermore, the present observation demonstrates that the freemartin condition in cattle can be induced even in cases where severe placental transformations had subsequently occurred and no foetus proper could be detected at delivery.