Estimation of variance components and heritabilities for growth traits in the Egyptian Dokki- 4 chickens using animal models
Abstract: Post-hatching growth traits of 7226 chick of Dokki-4 (as a native breed) were genetically evaluated. Records of individual body weight (BW) at hatch and biweekly thereafter up to 16 weeks of age were collected in two generations. Data of daily gain (DG) between intervals of hatch –4 ,4- 8, 8 – 12 and 12 –16 weeks were also used. Variance components and heritability estimates for these grows traits were estimated using DFREML procedure of single – trait (SAM) and multi-trait (MAM) animal models. Percentages of direct additive genetic variance (2A). for BW traits estimated by the MAM appeared to be higher than those estimated by the SAM. The percentages of 2A for BW traits ranged from 6.0 to 19.9% when using the SAM and from 9.6 to 17.8% when using the MAM. The percentages of common environmental variance (2A) for BW traits obtained by the MAM were higher (averaged 22.0% ) than those obtained by SAM(averged 17.4%). Little differences were observed in estimation of 2c between the SAM and MAM for analysis DG traits. Generally, estimates of heritability based on direct additive single- trait (h2As ) and multi-trait (h2AM ) animal models for all growth traits were low or relatively moderate. Estimates of heritability for BW traits resulting from MAM were somewhat larger (h2AM ranged from 0.10 to 0.18) than those obtained by SAM analysis (h2As ranged from 0.06 to 0.20). Most of the genetic correlations (rG) among growth traits at different ages were high and averaged 0.52 among BW traits and 0.25 among DG traits. All estimates of common environmental correlation (rc) among BW traits and among DG traits were positive and with moderate or high magnitudes.
Keywords:Body weight-gain weight-heritability- Genetic correlations variance components.
Publication year 2000
Pages 1905-1920
Availability location معهد بحوث الانتاج الحيوانى- شارع نادى الصيد- الدقى - الجيزة
Availability number
Organization Name
City مشتهر
serial title Annals of Agricultural Scence
Author(s) from ARC
External authors (outside ARC)
    ماهر حسب النبى خليل جامعة بنها
    محمود حنفى جامعة بنها
    محمود مغربى عراقى جامعة بنها
Agris Categories Animal husbandry
AGROVOC
TERMS		 Animal models. Body weight. Egypt. Growth. Heritability. Layer chickens. Weight gain.
Proposed Agrovoc variance components;Genetic correlations;variance;
Publication Type Journal
↑