This study aimed to estimate the heritability of milk yield (MY), fat percent (F%), fat yield (FY), protein percent (P%), protein yield (PY), somatic cell score (SCS), and total bacterial count score (TBCS) as well as to estimate the genetic correlations among these traits, using a dataset from 5,918 lactations of Jersey cows in Brazil. The covariance components were estimated by restricted maximum likelihood using the PEST and VCE6 programs. The average values obtained for MY, F%,