Decrease of percentage of carriers of bovine hereditary chromosome abnormalities.
The first carriers of the 1/29 and 14/21 translocations in AI bulls in Hungary were detected in 1975. The 1/29 translocation was found in Simmental, Swedish Red-and-White, Hungarian Grey, Blonde d'Aquitaine and Charolais cattle. The 14/21 translocation was found in a Simmental bull and its progeny. Until 1987, all AI bulls were state-owned. Translocation carriers were culled and their frozen semen was destroyed. Since 1987, the control programme has been carried on by the Hungarian National AI Programme. However, some privately owned bulls escaped culling. Beef bulls used in natural service mostly avoid the culling procedure. As a result of the control programme, Simmentals and Hungarian Greys are almost free of translocations. The 1/29 translocation still occurs sporadically in beef cattle.