Effects of Genotype and Oviposition Time on Egg Quality Traits of Commercial Laying Birds

This study aimed at investigating the effects of strain of layers and oviposition time on external and internal egg quality traits. The strains of layers used for this study are Isa Brown (IB), Bovan Nera (BN) and Dominant Black (DB). The time of oviposition investigated are 8-10am, 10-12noon, 12-2pm and 2-4pm. Freshly laid eggs were collected from the different strains during the aforementioned periods, and were taken to the laboratory for both external and internal egg quality analysis. Analyzed results showed that egg weight was not significantly (P>0.05) affected by strain. The three strains recorded similar mean values. Similar results were reported for other traits except egg length and shell thickness where significant differences were reported among the strains. BN and IB were superior to DB in terms of shell thickness. With regard to internal egg quality traits, significant (P<0.01) differences among strains were reported only for yolk weight and albumen width. Pertaining to oviposition effect, almost all the traits were significantly influenced by oviposition time. Both external and internal egg quality traits had superior (P<0.01) and higher mean values during morning than afternoon or evening collection. This might be due to very low temperature prevailing in the former and which encouraged the birds to eat more resulting to bigger egg size and higher egg compositions. Haugh unit in this study was not significantly affected by strain and oviposition time. It is suggested than management practices in laying farm such as lighting and feeding pattern be focussed on having more eggs laid in the morning session than afternoon or evening session.