The age and weight at first calving and other productive and reproductive traits are decisive because are important for the future performance of dairy cows, their analysis allows to define some goals related to the start of productive life of those, influencing direct economic cost of the period of growth and development. In this research, were estimated the heritability (h 2 ) and some genetic and phenotypic correlations of age and weight at first service, age and weight at fertile service, milk yield at first and second lactation and some other features related to the overall performance of cows during her life, which have wide importance in dairy cattle. Were analyzed 928 records of lactations of 184 Holstein cows born among the years 1985 to 2006 in a dairy herd in the department of Antioquia. The variance components were estimated by univariate and bivariate maximum likelihood methodology derivative free restricted and the correlations by direct estimation with phenotype information and estimated breeding values. The SAS 9.0 software was used for data editing and statistical analysis MTDFREML software was used for genetic analysis. The age and weight at first service did not have significant effect (P>0.05) on milk production in first and second lactation, neither with the total life production, However the age and weight at first fertile service had an effect highly significant (P<0.01) on production in first lactation. Heritability estimates for age and weight at first service were 0.29 ± 0.184 and 0.04 ± 0.170, age and weight at service fertile ± 0.41 0.195 ± 0.210 and 0.08 respectively.