Selection and correlated response for egg production traits in Inshas and silver Montazah strains of chickens [electronic resource].

Includes references.

Two local strains of chickens selected two generations for increasIng egg number up to 40 wks of age (Inshas strain) and egg weight at 40 wks of age (Silver Montazah strain) were used to study the changes in egg number and egg weight after selection and estimating correlated responses and genetic parameters of some economic traits. The results of selection for egg number at 40 wks of age showed significant differences between selected and control lines as well as among generations. The realized and expected response were 15.2 and 5.33 eggs over two generations. The direct selection for egg weight at 40 wks of age showed also highly significant differences among generations as well as selected and control lines. Moreover, the realized and expected response were 3.70 and 3.19gm over two generations. Heritability estimates for egg number at 40 wks of Jnshas strain based on sire, dam and sire plus dam components of variance were 02, 0 32 and 0.29, respectively, the corresponding estimates of egg weight at 40 wks of age in Silver Montazah strain were 0.52, 092 and 0.72, respectively. Negative genetic and phenotypic correlations were observed between egg number at 40 wks of age and age at sexual maturity, duration period of the first ten eggs, egg weight and feed conversion. However, positive correlations between egg weight at 40 wks of age and body weight at sexual maturity, age at sexual maturity, duration period of the first ten eggs and egg mass, while negative correlations with egg number and feed conversion were detected.

Summary in Arabic.

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