Genetic and environmental trends for post- weaning body weights in New Zealand White and Z- line rabbits using the animal model approch
Abstract: Genetic and environmental trends were evaluated for post- weaning body weights of 20677 weaned rabbits of New Zealand White (NZW) and Z- Line born between 1982 and 1996 from 1212 sires and 3168 dams. Multi- trait animal model was used for such evaluation taking into account body weight at 8 and 12 weeks of age. Heritability estimates for the two body weight in NZW were higher than those in Z- line; being 0.34 and 0.30 in NZW and 0.10 and 0.25 in Z- line at 8 and 12 weeks of age, respectively. Common litter effects were higher in Z- line (averaged 37.65%) than those in NZW (averaged 29.95%). All correlations between the two body weights were moderate or high; being 0.73 and 0.69 for genetic correlations, 0.60 and 0.64 for phenotypic correllatios, 0.49 and 0.64 for common- litter correlations and 0.45 and 0.68 for environmental correlations in NZW and Z- line rabbits, respectively. The ranges in predicated breeding values (PBV) for body weights at 8 and 12 weeks of age were 572 and 639 gram in NZW, while they were 216 and 449 gram in Z- line, respectively, i.e. wide variations in PBV of body weights between the two strains were in favor of Z- line rabbits. The accuracies ( ra) of minimum and maximum estimates of PBV were mostly higher in NZW than those in Z- line for the two weights; ranging from 0.48 to 0.73 in NZW and 0.38 to 0.62 in Z – line. Genetic trends indicate that PBV were mostly positive in NZW and negative in Z- line over the whole period of the study. In NZW rabbits, the trend indicates that the plateau for the breeding values reached soon at the beginning years, while in Z- line the rates of change in breeding values were very low during the five years of the study. Plots of year- season trends indicate that environmental effects ( i.e. seasonal – annual variations ) play a large role in improvement of the two body weight in both lines.
Keywords: Body weight, Animal model approach, heritability, correlations, breeding values, genetic trend.
Publication year 2002
Pages 89-101
Availability location معهد بحوث الانتاج الحيوانى-شارع نادى الصيد- الدقى- الجيزة
Availability number
Organization Name
City الغردقة
serial title 3rd Science Conference On Rabbit production in Hot Climates
Author(s) from ARC
External authors (outside ARC)
    محمود مغربى عراقى جامعة بنها
    علاء الرفا جامعة الاسكندرية
    ماهر حسب النبى خليل جامعة بنها
Agris Categories Animal husbandry
AGROVOC
TERMS		 Body weight. Dams. Fathers. Heritability. Rabbits.
Proposed Agrovoc genetic trend;breeding values;correlations;Animal model approach;
Publication Type Conference/Workshop
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