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Abstract
The present study was carried out using two broiler breeder strains imported from Germany (Sena (SS) and Lohmann (LL)) to find out the best mating combinations. The strains used either as a package matings or cross mating by exchanging the male for each strain. So as the breeding companies usually recommended using their strains as a package mating.
The objectives of this study were to compare the performance of the pure and the cross matings and to test the interaction between those genotypes and different levels of dietary protein and the effect of the interaction on their performance. The study also aimed to investigate genotype effect on hatchability to find out the best period where genetic improvement may take place.
The performance of the broilers produced from the different genotypes were evaluated using the following traits: mortality, feed consumption, feed conversion, body weight, weight gain and the European efficiency factor in addition to feed cost to produce one kg of live weight. Heterosis effect of cross genotypes and superiority over the female strain were also evaluated. The study objected to predict body weight at market age using day old chick weight, three-week body weight or both. At last the study aimed to investigate the effect of genotype on carcass yield and calculate the correlation coefficients between carcass parts.
(1 )Broiler breeder performance (The first experiment)
This experiment included four matings and two levels of dietary protein free from animal sources. The first level was 17.5% and the second level was 16%. The experiment was designed as factorial (4x2) with two replicates for each treatment in 16 pens. At 24 wk of age (first wk of production) 160 females and 16 males were housed in each pen. The experiment continued for 39 weeks of production (62 weeks of age).
(2) Broiler performance (The second experiment)
The second experiment was designed to study performance of the broiler offspring produced from the genotypes used in the first experiment. The broiler trial was conducted on 400 as hatched day old chicks, one hundred in two replicates from each genotype. Day old chicks were weighed and identified with wing band number to be able to follow the weekly body weight
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