ADDITIVE AND HETEROTIC COMPONENTS FOR POST-WEANING GROWTH TRAITS IN A CROSSING PROJECT OF V-LINE WITH GABALI RABBITS IN EGYPT

This study was carried out within a four years project that aims to develop a synthetic line (M) between the Sinai Gabali breed (G) and the V-line (V). Data of 6278 young rabbits sired by 242 sires and dam reared by 540 dams coming from six different genetic groups of rabbits (represented by G and V purebreds and their crosses; F1, F2, F3 and M line) were used. The recorded traits were: body weight at weaning (BW4), 8 (BW8) and 12 (BW12) weeks of age, as well as daily gain during intervals of 4-8 (DG4-8) and 8-12 (DG8-12) weeks. Using mixed model methodology, estimable functions of genetic type effects were computed and based on them and the matrix of their variance-covariance errors, the crossbreeding parameters were estimated. It was discussed which parameters could be accurately estimated concluding that no matter six genetic groups were involved, only the difference between G and V for the direct additive effects (DG-V), the individual heterosis (H I) and the maternal heterosis (H M) should be considered. The results showed that the differences between G breed and V line were significant for almost all the studied traits, in favor of G breed. Means of F