RESUMEN
The Venezuelan Creole breed cattle is a Bos taurus well adapted to tropical conditions; however, it has demonstrated a low fertility rate. Recently, improvement in animal production by selection based on chromosomal analysis has allowed for the erradication of abnormalities involved in fertility problems, especially that of the 1 29 translocation. In the present work chromosomal analyses were carried out on 60 Creole bulls. Heparinized peripheral blood cells were cultured rendering metaphase spreads and subsequently stained by G- and C-banding techniques. The 1 29 translocation was observed in 13 of the 60 bulls. The occurrence of this translocation in Creole cattle is discussed.
RESUMEN
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.