Data on 51 sires and 209 daughters (pater-nal half-sisters) of Bauscat (B) and Giza White (G) rabbits were used to obtain heritability estimates for some litter traits (litter size and gain at weaning, preweaning litter mortality and mean kit weight at weaning) and the genetic and phenotypic correlations among these traits. Estimates of heritability for litter traits studied (except preweaning mortality in B rab-bits) were moderate or high. HeritabiIities for litter traits studied in G were substantially higher than the corresponding estimates in B rabbits. Genetic and phenotypic correlations between litter size and litter gain were posi-tive and relatively large. The genetic and phe-notypic correlations between litter size and mean kit weight of B rabbits were negative while the reverse was observed for G rabbits. Litter gain and mean kit weight were positively corre-lated both genetically and phenotypically. As expected, direct selection was shown to give greater improvement in litter gain and mean kit weight than indirect selection. Selection for litter size has been generally associated with a predicted correlated decrease in mean kit weight while giving a high positive response in litter gain. |
