The effect of oviposition time and genotype on egg quality characteristics in egg type hens

Abstract

In an experiment with three strains of Dominant genotype the effect of oviposition on egg quality characteristics was investigated. Laying hens of the Blue strain (group 1), Plymouth Rock (group 2) and their F1 cross (group 3) from 20 to 64 weeks of age were housed on litter (9 birds per m2). The collection time was at 6.00, 10.00 and 14.00 h. Eggs were gathered in a 28-day interval, every two days all produced eggs (720 eggs in total). The time of oviposition was influenced by genotype. The highest number of eggs was collected in the Plymouth Rock strain at 6.00 (53.5%) and the lowest in the Blue strain at 14.00 (11.1%). There were interactions between the time of oviposition and genotype in egg weight. Eggs laid in the morning at 6.00 were significantly heavier (60.5 g, 64.9 g and 62.1 g) in comparison with eggs laid in the afternoon (59.3 g, 62.4 g and 62.7 g). The heaviest eggs were produced by the Plymouth Rock strain. Significant interactions were observed in eggshell weight when the heaviest eggshell was in afternoon eggs (5.6 g, 5.8 and 5.9 g) and F1 genotype. The egg shape index was also affected by the genotype and time of oviposition. Among the albumen quality characteristics only Haugh Units were influenced by genotype and significantly higher numbers were determined in the Plymouth Rock strain (85.0, 85.3 and 84.7). The genotype significantly affected also the yolk index which was the highest in F1 genotype (45.4%, 45.4% and 44.5%).