ESTIMACIóN DE PARáMETROS GENéTICOS PARA CARACTERíSTICAS PRODUCTIVAS Y REPRODUCTIVAS EN LOS SISTEMAS DOBLE PROPóSITO DEL TRóPICO BAJO COLOMBIANO

in order to estimate the variance components, heritabilities, repeatabilities, and genetic and phenotypic correlations for the milk yield (my), weaning weight (ww), calving interval (cii) and cow index (iv) of bovine females handled in dual purpose production systems in the colombian low tropic, productive and reproductive records of 1687 cows registered in the colombian dual purpose breeders association (asodoble) were analyzed during the period from 1998 to 2007. amixed animal model which included the fixed effects of the contemporary group (farm-sex-season-year), breed composition and lactation length as a covariate; as well as the random animal genetic effects and the permanent and residual environment was used. estimated heritabilities for ci (0.04) and ww (0.11) were low, and moderate for my (0.35) and iv (0.24), respectively. estimated repeatability for iep was low (0.08) and for my (0.41) and iv (0.31) moderate; in the case of ww this value was equal to the heritability (0.11). genetic and phenotypic correlations obtained between my and ww over ci were positive, and a negative genetic association between my and ww was determined. the results showed that the iv is a good indicator, from the standpoint genetic, of productive and reproductive efficiency of animals handled in these production systems.