Effect of Seasonal Variation on the Meiotic Rate and Some Fitness Component In Rabbits

SUARYThe present investigation carried out to study the effect of seasonal changes on the rate of Meiotic divisio ixi the local Baladj strain of rabbits.The effect of seasonal variation on some fitness cotnp— onents in Baladi and other imported breed,narnelly Bouscat were carried out and average body weight, viability and sex ratio were recorded for the offspring. The fitness components were estimated at different periods of animal ages. The results obtained in this investigation indicated that :— 1 — The freq2 — The frequencies of the diffrent Meiotio stages showed cosidrable reduction in the different Meiotic stages show. ed considerable reduction in the percentage of different stages during the summer than the winter season.3 _ mean litter size was generally kigher in Bouscat than in Baladi rabbits.4 — seasonal changes had little effect on litter size in Bouoat rabbits.5 — Both strainsshowed a trend of decline in mean littersize with progressive littering order,although differeces between concecutve litters were very small.6 — The Bouscat strajnhad greater body weight than the Baladi either during the summer or during the winter season. At 60 days of age,the average body weight in the two strains born during winter season was higher than that ob1.nd for mdi — viduals born d7 At 105 days of age the effect of seasonal variation on body weight were not significant.8 — In baladi rabbits study of the effect of litter sequence On body weight showed that it was higher in the third litter than in the first litter at 105 days of age.Ia contrast, mean body weight of Bouscat showed a trend of decline in the second and the 9 — The percentage of viability at 15 days of age in Baladi rabbit born in summer was relatively little higher than that obtained for individuals bor during winter season. On the other hand, in Bouscat rabbits the percentage of viability at that age was i10 — At 60 days of age ,the viability in Bouscat str4in con — siderably declined by about 10 — IS % below the value obta — ied for the same groups occurred between 14 and 6 days than that at 2 weeks of age.II — Ba].adi rabbit had relatively short gestation periodthan Bouscat rabbit. There was no significant differences in gestation period between summer and winter seasons.II — At 60 days,body weight in the crosses between Baladi and Bouscat was relatively higher than the mid parent level,the differences between body weight in Baladi end the crosses were highly significant.14 — The viability. in the crosses increased by about 20 % than the Baladi strain and 30 % than the Bouscat one.14 — In Baladi strain sex ratio was I: I while in Bouscat breed this ratio was about I :0.6 in faTour of females.