GENETIC EVALUATION FOR EGG QUALITY TRAITS IN CROSBREEDING EXPERIMENT INVOLVING MANDARAH AND MATROUH CHICKENS USING ANIMAL MODEL By

Abstract: A crossbreeding experiment was carried out between two Egyptian strains namely Mandarah (MN) and Matrouh (MA). Forty sires and 450 dams from each strain were used to produce four genetic groups (two purebreds of MNxMN and MAxMA and two crossbreds of MNxMA and MAxMN). Three eggs were taken in successive three months from each daughter within each strain and their crosses (608 daughter) to study the egg characteristics with a total number of 1735 eggs. Egg components such as egg weight (EW), albumen weight (AW), yolk weight (YW), shell weight (SW), and Haugh units (HU); shell characteristics such as shell thickness of narrow (NST), equatorial plan (EST) and broad (BST) regions and egg specific gravity (ESG); and shape indexes such as egg shape index (ESI), albumen index (AI) and yolk index (YI) were studied. Multi-trait animal model was used to analyze the data of egg quality. MN had the highest means of egg components, ESG and shape indexes, while MA had the highest means for most shell thickness traits. Estimates of heterosis were positive for most egg components and shape indexes as well as for ESG. While, they were negative for YW, SW and shell thickness. Heritability estimates were moderate or high for egg components (ranged from 0.25 to 0.67), but they were low for HU, shell thickness and shape indexes (ranged from 0.002 to 0.17). Pullets mothered by MN and sired by MA gave an advantage in most egg quality traits over the reciprocal cross