Data on 218 litters of Bauscat (BB) and Giza White (GO) rabbits were analyzed to study the effects of some non-genetic factors, and the genetic factors of sire of doe and doe within sire. Traits considered in the analysis were: doe's weight at conception (BWC) and at 1st (BW1), 2nd (BW2), 3rd (BW3) and 4th (BW4) weeks of gestation and litter size (LSB) and weight (LWB) at birth. Heritability, repeatability and phenotypic correlation parameters for these traits were estimated by mixed model analysts.
Weight of BB does exceeded that of GG does at conception and during gestation. LSB and LWB of GG were higher than those of BB. Birth year of sire and year of production effects on doe weight, LSB and LWB were not significant for BB and GO rabbits. Month-of-conception and parity effects on LSB and LWB were not significant for BB and GO rabbits, while they were significant sources of variation in most weights of BB and GG does during gestation. BB does conceived during September and October had the heaviest weights. The smallest size and lightest weight of litters were recorded for those BB does conceived during December while the largest and heaviest litters were recorded during Januarys No consistent patterns for parity and month-of-conception effects on doe weight and litter traits of GO rabbits were observed. Effects of sire of doe within year were significant (P < 0.05) for BWC of BB rabbits, all weights of GO and litter traits of BB but not significant for BB doe weight during gestation and litter traits of GO. Differences in doe weight due to doe effects were significant (P < 0.001), while they were not significant for litter traits in BE and GO rabbits. The percentages of variation due to sire effects were larger for GO than for BB doe weights, while a reverse trend for Litter traits was observed. Estimates of heritability for BWC, BW1, and BW2 of BB ranged between 0.06 to 0.34, while no estimates were obtained for BW3 and 5W4. Heritability estimates for GO doe weight ranged between 0.50 (BW1) and 0.79 (5W2). Heritability estimates for LSB was 0.44 for BB rabbits, while no estimates were obtained for GO; the estimate for LWB was 0.37 and 0.10 for BB and GO, respectively. Repeatability esti-mates for all weights of doe and litter traits studied were higher for BB than for GO rabbits. The phenotypic correlations between doe weight and litter traits studied were positive and of moderate magnitude.
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