Data from 12.840 litters, recorded from 1989 to 2003, were used to evaluate genetic parameters and genetic trends of reproductive traits in Large White pigs. Data were provided by the Swine Breeders Brazilian Association - ABCS and included records on litter size at birth (NLN), litter size at 21 days (NLD), average litter weight at birth (PMNasc), litter weight at weaning adjusted to 21 days (PMD), average daily weight gain (GMD) and number of stillbirth (NatMort). Variance components were estimated by REML using a model that included the contemporary group (herd-year-season of farrowing) and the covariates number of farrowings, age of the sow at the first and at the last farrowings as fixed effects; and the direct genetic, maternal, common litter and residual random effects. Direct genetic and maternal genetic trends were estimated by regression of breeding values on birth year of the dam. Genetic trends for direct and maternal genetic effects were significant for all traits, except for the maternal genetic effect for NLN. Estimates of direct and maternal genetic gains were, respectively, 0.0019 and 0.0002 piglets/year for NLN, 0.0019 and 0.0005 piglets/year for NLD, -0.0292 and 0.0162 g/year for GMD, -6E-05 and 4E-05 g/year for PMNasc, -0.0013 and 0.0006 g/year for PMD and -0.0014 and -0.0005 piglets/year for NatMort.
direct and maternal genetic effects; genetic trends; litter size; litter weight; stillbirth
