title: Incidence of 1/29 translocation in Venezuelan Creole pure and crossbreed cows used in reproductive programs.
abstract: The Venezuelan Creole breed cow has shown great versatility in adapting to extreme tropical conditions, but unfortunately it has exhibited low fertility. In a previous study conducted at the Experimental Station Guárico in Calabozo, Venezuela, chromosomal analysis of 30 Creole bulls demonstrated the presence of Robertsonian translocation 1/29 (Rb 1/29) in 16.6% of the animals. Considering this finding, we sought to establish the incidence of Rb 1/29 in Creole cows. Thus, heparinized peripheral blood cells were cultured rendering metaphase spreads and were subsequently stained by Giemsa and G-banding techniques. The chromosomal diagnosis was performed in 2 groups of cows (21 pure Creole and 47 hybrids Creole x Brahman). The results confirmed the presence of Rb 1/29 in females as had already been demonstrated in bulls. In the first group of cows the incidence of Rb 1/29 was 4.8%; in the second it was 8.5%. The implication of this finding is discussed here.
authors.affiliation: Departamento de Biologia de Organismos, Laboratorio de Reproducción y Desarrollo Animal, Universidad Simón Bolivar, Caracas, Venezuela.
authors.forename: M G
authors.initials: MG
authors.lastname: Muñoz
authors.forename: D
authors.initials: D
authors.lastname: Ocanto
authors.forename: R
authors.initials: R
authors.lastname: Medina
authors.forename: M I
authors.initials: MI
authors.lastname: Duraes