A crossbreeding experiment was executed between the local strain of Golden Montazah (GM) and a
White Leghorn (WL) strain-breed. Data on 996 pullets from 79 sires and 441 dams were produced for
five genetic groups (two purebreds and three crossbreds). Crossbreeding effects (direct additive effects,
direct and maternal heterosis, and direct recombination) for age traits (ASM) and body weight
(BWSM) at sexual maturity, weight of the first egg (WFE), egg number (EN90D) and egg mass
(EM90D) during the first 90-days, total egg number (EN120D) and total egg mass (EM120D) during
the 120-days of laying, and rate of laying egg per day during 90 days (RL90D) and 120 days (RL120D)
were estimated. Partial recording traits such as period (days) in which first ten eggs were laid (PF10E),
egg mass for first ten eggs (EMF10E), egg number (EN2D/W) and egg mass (EM2D/W) for two days
per week, egg number (EN1W/M) and egg mass (EM1W/M) for one week per month, as well as pause
periods during 90 days (PP90D) and 120 days (PP120D) were also studied. Single-trait animal model
analysis was used to analyze the data of egg production traits.
Results showed that WL strain had superiority in most of the studied traits compared to GM, but GM
strain had significantly heavier BWSM and WFE than WL. Averages of most of the traits studied in
crossbreds were higher than purebreds. Percentages of direct additive effects were mostly positive
(P |
