Effectiveness of genetic evaluation with transformed data by using dam-daughter pairs Japanese quails

In estimation of variance components with REML it has been assumed that the data were normally distributed. Egg production traits of poultry have been shown to exhibit markedly non-normal distributions. In this study, six tra its from an unselected quail line were analysed. The original data were tra nsformed using the well-established power transformation to approach normal ity. The genetic evaluation was carried out with a multiple-trait animal mo del, based on transformed and untransformed data, respectively. Two traits of laying performance, of egg weight and body weight were analysed simultan eously. To compare the efficiency of breeding values the method of simulate d selection with biological data (dam-daughter pairs) was used. To select t he dams with intensities between 10% and 90% we used individual records and BLUP-breeding values, estimated with transformed and untransformed data. T he response of such a selection was estimated using the corresponding daugh ter records. Only for the trait laying performance up to 200 days of life w e could indicate an advantage of the transformation. It was shown, that by changing from one trait to multiple-trait genetic evaluation non-normality could be compensate. For 10% intensity the selection for individual laying performance provided an unexpected high response in comparing with the BLUP -method.