Genetic parameters for swine carcass traits .1. Estimates of heritability

Four hundred and twelve Large White swines were used to evaluate the heritability for fifteen carcass classification and dissecation traits. A complete data set, with an equal number of observations for each characteristics, was analyzed using animal model and DFREML procedures. Two models were used: Model 1 with the basic mixed models, including only the additive genetic effect of the animal (AGEA); and Model 2, including AGEA and common environmental effects of litter (CEEL). Analyses from Model 2 indicated a significant reduction in (h) over cap(2)- estimates. The (h) over cap(2)-estimates of carcass lenght, loin eye area, lean-fat relationship and percentages of lean cuts and fat, indicated that these variables showed a good response to selection in breeding programs. The estimated values for CEEL showed that these effects were responsable for an important fraction of phenotypic variance, and indicated that data sets must avoid litters with few individuals in each subclass which may cause the absorption of AGEA by CEEL. It is more important the structure than the number of data in small data set (less than 1000 observations).