| Abstract: |
Data of the present study was obtained from rabbitry farm belonging to Animal Research Center, Animal Production Department, Faculty of Agriculture, Zagazig University, Zagazig, Egypt, spreading over three consecutive years of production from August1986 to July1988.The present study was carried out to estimate heritabilities, common litter effects, breeding values for each progeny and genetic correlation among traits for post-weaning live body weight at 5, 6, 8, 10 and 12 weeks of age and daily weight gain at the intervals of 5-6, 6-8, 8-10, 10-12 and 5-12 weeks of age in New Zealand White and Californian rabbits raised under Egyptian conditions using an updated methodology.The results obtained could be summarized:New Zealand White rabbits (NZW) recorded better performance in post-weaning growth for live body weight (LBW) and daily gain (DG) traits than in Californian (Cal) rabbits.For both breeds, percentages of Coefficients of variation (CV%) for LBW at earlier ages in NZW and Cal were higher than at older ages where CV% ranged from 14 to 23% for live body weight and from 18 to 36% for daily gain in NZW rabbits, while it were ranged from 15 to 24% for body weight and from 18 to 34% for daily gain in Cal rabbits.Heritability estimates were low in both breeds and ranged from 0.08 to 0.13 in NZW and 0.10 to 0.14 in Cal rabbits, for live body weight and from 0.08 to 0.13 and 0.05 to 0.11 for daily gain in NZW and Cal rabbits, respectively.Common litter effect (σ2c) estimates were in general, although it was higher in NZW than Cal rabbits.Generally, estimates of males breeding values (MBV) for body weights and daily gain were higher in NZW than Cal male rabbits except in live body weight at 12 weeks of age.Also, estimates of females breeding values (FBV) for live body weight and daily gain were higher in NZW than Cal female rabbits except live body weights at 6 and 12 wks of age.Estimates of genetic correlation (rG) were differed. These estimates in NZW rabbits ranged from 0.61 to 0.95 between live body weights at 5 & 6 and 5 & 12 wks of age, while for Cal rabbits ranged from 0.55 to 0.93 at the same intervals.Estimates of genetic correlation (rG), between daily gain intervals for NZW rabbits ranged from 0.37 to 0.79 between the intervals of 5-6 & 10-12 and 8-10 & 10-12, and 0.31 to 0.71 for Cal rabbits, between the intervals of 8-10 & 5-12 and 6-8 & 5-12 wks of age, respectively.
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