A crossbreeding experiment was carried out involving New Zealand White (N)- and Egyptian Gabali (G) rabbits to produce six genetic groups of MV, GG, 1/2G11.7N,112M/2G, 34GiliN and 3/4NI/4G. Estimates of direct (GI) and maternal (0) additive effects, direct or) and maternal (Hg) heterosis and direct recombination effects (RI) were genetically evaluated for litter size at birth (MB) • and weaning (LSPI) and litter weight at weaning (L WW). N rabbits had superior performance in litter size and weight compared to 'G rabbits. Crossbred litters obtained from mating N bucks with G does were generally associated with superiority •contpared to those litters obtained from the reverse mating. In most cases, genetic group of 1/2NI/2G gave larger litter size and heavier litter weight compared to the other genetic groups. The estimates of crossbreeding effects for LSB, LSW and LWW were 2.62, 7.52 and 12.37 % for 64, -2.34, -9.56 and -7.50 %for GM, 9.5, 19.2 and 15.8 % for Hi; 3.43thid -3.77 % for it", and 45.5, 17.8 and 23.8 % for RI, respectively. The estimates of direct additive effects were moderate or high and in favour of N rabbits and consequently N bucks could be used as sires in crossbreeding Stratification systems under hot climatic conditions. The estimates of G" for all traits were somewhat low and in favour of G rabbits. Crossbred dams recorded favourable maternal heterotic effects on litter size at weaning and unfavourable maternal heterotic effects on litter size at weaning, i.e. crossbred dams recorded larger litter size at weaning associated with a reduction in litter weight at weaning than their crossbred daughters. Estimates of direct recombination effects.for litter size and weights at weaning were insignificant and indicate that epistatic recombination effects for crossbred litters during the suckling period were negligible. |
