[Chromosomal analysis of Venezuelan creole cattle]

In order to improve the animal production by artificial selection, the chromosomal analysis of 15 (9 bulls and 6 cows) Venezuelan Creole cattle--a well adapted dual purpose herd--was conducted. This particular herd has a low fertility related to a diminished non return rate. Heparinized peripheric blood cells were cultured rendering metaphase spreads and subsequently stained by the G- and C-banding techniques for identification of chromosomes. All bulls had the submetacentric Y chromosome characteristic of Bos taurus taurus. The 1/29 translocation was observed in 2 bulls (22.2% of all males studied). The fused chromosome showed a single centromeric block of heterochromatin. The presence of such translocation in the Creole sample associated with reduced cattle fertility, demonstrates the urgency to continue this kind of study, in order to determine the incidence of this problem in Venezuela.