1. Three-year crossbreeding experiment involving Baladi Saudi (S) and White Leghorn (L) chickens was carried out in El-Qassim region in Saudi Arabia to evaluate the egg production performance and egg quality traits of the resulting crossbreds.
2. Data of age at first egg, first three-month egg production (EP3), annual egg production (AEP), egg weight (EW), albumen weight of egg (AW), yolk weight (YW) and shell weight (SW) were collected on 696 hen.
3. The genetic model of Dickerson under multi-trait animal model was used to estimate the heterotic components of this experiment in terms of direct (GI) and maternal (GM) additive effects, direct (HI) and maternal (HI) heterosis, and direct recombination loss (RI).
4. Variance components, heritabilities and breeding values for these egg traits were predicted using DFREML procedure of multi-trait animal model.
5. Hens of L breed had superior performance in egg production and egg qualities traits compared to the S hens.
6. Percentages of direct additive genetic variance ( ) for egg traits were moderate or high. Heritabilities of AFE, EP3 and AEP were larger than those of egg quality traits. Estimates of heritability ranged from 0.31 to 0.55 for egg production traits, while they ranged from 0.22 to 0.29 for egg quality traits.
7. The ranges in breeding values for birds with and without records for egg traits were generally moderate or high. The accuracies of PBV were high and nearly similar for most traits studied.
8. The direct additive effects considerably affected most traits. L-sired hens had high direct additive effects (GI) compared to the S-sired hens for all traits studied.
9. Additive maternity (GM) for studied traits was cosiderable and in favour of the S breed since hens produced from SXL matings had better egg production than those produced from LXS matings.
10. Crossbred hens recorded positive direct heterosis for some egg production traits and negative HI for egg quality traits. The percentage of HI was about 3.2% for egg production traits, while they ranged from –14.0 to –2.5% for egg quality traits.
11. Estimates of HM for EP3 and AEP in daughters of crossbred dams were positive along with favourable negative HM for AFE.
12. Direct recombination losses (RI) in crossbred hens for AFE, EP3 and AEP were –4.7 days, 1.31 egg and 4.09 egg, respectively.
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