Estimates of genetic and phenotypic parameters for performance traits in paternal broiler lineages selected during 12 generations were obtained through mixed models methodology. Data consisting of body weight (P42), breast length (CPeito), largest (Larg1) and smallest (Larg2) breast widths recorded at 42 days of age in approximately 46,000 birds between 1992 and 2003 provided by CNPSA/EMBRAPA were used to estimate (co)variances by REML. The heritability estimates were moderate, ranging from 0.29 to 0.53. Genetic correlations estimates between P42 and CPeito, Larg1 and Larg2 were 0.68, 0.65 and 0.48 respectively. Genetic trend estimates indicate that progress has been obtained by selection on the performance traits.
broilers; genetic parameters; genetic trend; mixed models; REML
