Indigenous layer’s performance as influenced by breed, age of the breeders and season of the year

الملخص EN

The present study was designed to study and evaluate the effects of breed (Dandarawi or Sinai), age of the breeder hens (24 - 48 wk) and three seasons of the year on layer performance, egg quality and their correlations.

The following results were obtained: Significant breed differences were found for egg weight (EW), hen day for long period, 24 wk (HDLP%), specific gravity (SG), air cell height (ACH), percentages of albumen, yolk, yolk to albumen %, shell thickness (ST), yolk index (YI), Haugh unit (HU), percentages of moisture, ash, fertility and hatchability.

Spring had significantly higher HDLP%, shape index (SI) and ACH than other seasons.

Heavier eggs associated with higher SG were laid during summer than those laid during spring or winter.

Egg’ yolk cholesterol concentration (EYCC) showed inconsistent differences as age of the breeder hen progressed.

Internal egg quality traits, eggs’ chemical composition, blood serum cholesterol concentration (BSCC) and either fertility % or hatchability % were significantly affected by age of the breeder hens.

Variations in egg performance traits were, perhaps, caused mostly by physiological changes associated with aging and environmental effects.

The one important genetic effect was breed differences in EW, internal quality traits and hatching characteristic.

Seasons of the year were significantly affected chemical composition traits and BSCC and EYCC.

Sinai was more sensitive to age effect than Dandarawi for eggs’ chemical composition and cholesterol determination in egg yolk and plasma traits and hatching characteristics.

Eggs’ chemical composition and cholesterol determina-tion in egg yolk during different seasons of the year were more sensitive to age of the breeder than other studied traits.