PROBABLE ABSENCE OF THE 1 29-ROBERTSONIAN TRANSLOCATION IN THE BELGIAN-BLUE BREED OF CATTLE/

The 1/29 translocation, a structural chromosomal abnormality, is often associated with infertility. For this reason, we wished to know its f requency in the Belgian Blue breed. In this study, none of the 138 Bel gian Blue bulls karyotyped carried the 1/29 translocation. We calculat ed that the 1/29 translocation frequency in the Belgian Blue breed mus t be lower than 0.69% at the 5% level. This result can be explained by the origins of the breed. The Belgian Blue breed is descended from fo cal dairy breeds and from the Shorthorn breed, which can all be consid ered to be free of the 1/29 translocation.