الفهرس 
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Abstract
The objectives of this study were to investigate the effect of breed and parity on doe reproductive traits with estimation of genetic parameters for litter traits in three breeds of rabbit (New Zealand White, Flander and Rex). Moreover, evaluation of buck seminal traits in these breeds was also carried out. Six does and two bucks from each breed were used in this study. The data recorded included doe weight at first mating, gestation length, number of service per conception, conception rate and kindling intervals. Genetic parameters were also estimated for litter traits (litter size at birth and weaning, litter weight at birth and weaning, average kit weight at birth and weaning and pre-weaning mortality). Also, the analysis concerned buck’s semen characters in these rabbit’s breeds. The recorded traits were: pH, ejaculate volume, sperm mass and individual motility, concentration, live and dead sperm percentage, percentage of abnormal sperm and total sperm output per ejaculate. Flander does showed significantly the highest initial body weight at first mating (3.06 kg). While, the lowest one was exhibited in NZW does (2.53kg). On the other hand, non-significant differences were reported between breeds for NSC, GL, KI and CR %. In respect to parity, significant differences in NSC, GL and CR % were demonstrated. The heritability estimates for litter traits were moderate to high (0.40 to 0.80) and tended to increase from birth up to weaning (28 days). With regard to semen evaluation, the results showed that rabbit breed with the exception of pH had a significant effect on all semen quality traits. Determining the progesterone receptor gene that responsible for uterine capacity by using PCR-RFLP for F2 generation of the breeds under investigation. A total of 50 kits from F2 of the breeds under study at four week of age were used. The results revealed that the homologous genotype AA was more frequent (0.31) in the high line of rabbit breeds (Rex) than the low line breed (NZW) which found to be zero. While, the other homologous genotype GG was found to be zero in the high line of rabbit breed but showed highest frequency in the low line rabbit breed (0.33).The allele A found in 65% of the high line rabbit breed and in 33 % of the low ones. While, the allele G found in 35% of the high-line rabbit breed and in 67 % of the low ones.