A Comparison of four methods of estimating variance components and heritability for growth traits in chickens
Abstract: Data of 1137, 916and 1030 Silver Montazah (SM).Golden Montazah (GM)and matrouh (MA) chicks respectively. Were used in this study.
The studied characters were body weight at hatch.4,8 and 12 weeks of age. Daily gain and relative growth rate during the periods of hatch 4 weeks. 4-8 weeks and 8-12 weeks of age. Variance components and heritability estimates based on sire components were estimated using Hendroson’s method 3(H3). Maximum likelihood (ML). Restricted maximum likelihood (REML) and minimum variance quadratic unbiased estimates (MIVQUE). Variance components of sire effect (2 ) for most of growth traits in MA and SA chickens were higher than those obtained in GM, percentages of 2 for some of growth traits for all strains determined by REML procedure were high compared to most percentages obtained by the other procedures (c.g.H3.ML and MIVQUE). Results show that biased estimates in variance components of sire and error effects for growth traits in GM chickens were relatively higher than those obtained in SM and MA strains. Biased estimates in variance component of sire effect obtained from REML method for most of growth traits in the three strains were lower than those computed from H3 and MIVQUE methods. Estimates of heritability from sire components (h2) in MA chickens were higher than those estimates of SM and GM chickens. Heritability estimates by REML,ML,H3 and MIVQUE procedures in the three strains for the studied growth traits were variable, while estimate of h2 resulting from REML were unbiased by selection commonly. It was concluded that likelihood procedures (ML and REML) were superior for estimating variance components and genetic parameters from unbalanced data. The growth traits in the NM strain could be by individual selection.
Keywords: body weight, gain, breeding values, variance componant.
Publication year 2000
Pages 345-358
Availability location معهد بحوث الانتاج الحيوانى- شارع نادى الصيد- الدقى - الجيزة
Availability number
Organization Name
City سخا
serial title Proceeding Conference Animal Production in the 21th Century
Author(s) from ARC
External authors (outside ARC)
    محمود مغربى عراقى جامعة بنها
    عزت عطا عفيفى جامعة الزقازيق
Agris Categories Animal husbandry
AGROVOC
TERMS		 Body weight. Breeding value. Chickens. Growth. Heritability.
Proposed Agrovoc growth traits;variance componant;
Publication Type Conference/Workshop
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