SELECTION FOR GROWTH AND NURSING ABILITY IN BALADI RED RABBITS -DIRECT RESPONSES | ||||
| Journal of Animal and Poultry Production | ||||
| Article 1, Volume 27, Issue 5, May 2002, Page 2837-3847 PDF (331.18 K) | ||||
| Document Type: Original Article | ||||
| DOI: 10.21608/jappmu.2002.254715 | ||||
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| Author | ||||
| G. E. Y. Attalah, | ||||
| Department of Animal Production, Faculty of Agriculture, Al-Azhar University, Nasr City, Cairo. | ||||
| Abstract | ||||
| A selection experiment, for high 4-week body weight and high litter weight at weaning (4 weeks), was carried out for three generations of Baladi Red rabbit. A total number of 18 bucks and 48 does were taken from the third generation of the base population to construct the initial generation of selection. The animals were randomly assigned to three mating groups, the first group (G) was established by selection for high individual body weight at 4 weeks of age and the second was established by selection for high litter weight at weaning (M), while the third was maintained as a randombred contemporary control (C) . The results obtained were as follow: Individual body weights at 4 weeks of age (BW4) in line (G) were increased significantly (P<0.01) from 314.2 g at the first generation to 339.8 g at the third generation, while there were no significant differences in body weight at 4 weeks of age for the control line. Rabbits of the selected line gained 5.35% more than those of the control line at the third generation of selection. Litter weights at weaning (LW4) in line (M) were increased significantly (P<0.01) from 1610.2 g at the first generation to 1654.1 g at the third generation, while there were no significant differences in litter weight at 4 weeks of age for the control line. Litter weights of selected line were 3.83% more than those of the control line at the third generation of selection. Both BW4 and LW4 were significantly affected by generation, line and dam; while the effect of sire was not significant. No significant differences were detected between the expected and actual selection differentials for both characters (BW4 and LW4) through the three generations of selection. The realized response to selection for BW4 decreased from 4.6 g at the first generation to 2.1 g at the third generation, while that for LW4 decreased from 7.2 g at the first generation to 4.6 g at the third generation. Heritability of BW4, calculated from the sire variance component was 0.26, and that calculated from the dam variance component was 0.54, while that obtained from the sire plus the dam variance components was intermediate between the two estimates, it was 0.40 and the realized heritability ranged between 0.49 and 0.63. Heritability of LW4, calculated from the sire variance component was 0.34, and that calculated from the dam variance component was 0.56, while that obtained from the sire plus the dam variance components was intermediate between the two estimates, it was 0.45 and the realized heritability ranged between 0.53 and 0.67. | ||||
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