Genetic evaluation of growth traits in a crossbreeding experiment involving line V and Baladi Black rabbits in Egypt.

Abstract

Five genetic groups of rabbits were produced in a crossbreeding experiment involving the Spanish synthetic maternal line V, Egyptian Baladi Black (BB), their first reciprocal crosses (F1) and the second generation (F2) by inter se mating of the F1 to evaluate their body weight (BW) and daily weight gain (DG) from weaning (4 weeks) to marketing (12 weeks). A total of 2622 rabbits coming from 24 sires and 114 dams (892 purebred and 1730 crossbred progeny) were controlled to evaluate these genotypes. The study was conducted through two successive years during the first four parities of 114 dams. Statistical model included the fixed effects of animal genotype, year-season, parity order and sex along with the random effect of environmental common litter effects and additive genetic values. Crossbreeding genetic parameters (direct and maternal additive effects, direct and maternal heterosis) were estimated. Highly significant differences (P<0.001) were detected for all fixed effects on all traits. Estimates of crossbreeding genetic parameters showed a superiority of line V fryers compared with other genotypes, and Baladi Black had the poorest performance. Estimates of direct heterosis (7 to 11.8%) and maternal heterosis (-0.4 to 7.4%) mainly showed significant positive effects for crossing on growth traits. Estimates of direct and maternal genetic effects showed a positive pattern in favor of line V. The growth traits were significantly affected by direct genetic effects. The maternal effects were less important. These results suggest that applying crossing between line V and Baladi Black rabbits could be an effective breeding method for producing fryers superior in growth traits in Egypt.