A Robertsonian translocations in the female cells of a bull, co-twin to a freemartin

A case of 1/29 chromosome translocation in a male calf of the Brown Swiss breed is reported. Except for the aggressive behavious, the subject showed clinically nothing peculiar. A post-mortem examination did not reveal any internal macroscopic malformation. Since many reports indicate that such a type of translocation, found in a wide range of breeds of Bos taurus of several countries, seems to be linked with a lowering of fertility, the authors feel that chromosome screening might play an important role in breeding programs in the immediate future.