The influence of rearing system and age on the phenotypic correlation of the physical properties of eggs of Banat naked neck layers

Abstract

The aim of the study was to examine the influence of the rearing system and age on the phenotypic correlation of the physical properties of the eggs of the Banat naked neck layers. In both examined systems (extensive and semi-intensive system) there were 50 Banat naked neck layers each. The egg properties were examined at three evenly distributed time intervals (40, 45 and 50 weeks of age) in the period from May to July. In order to determine the external properties of egg quality, three basic measures were observed: egg weight, egg length and egg width. Based on the measured length and width of the eggs, the egg shape index was calculated, and subsequently the volume and surface area of the eggs were determined. For each examined factor, the correlation between the mentioned characteristics was determined. The obtained results showed a significant effect of the rearing system on all examined egg properties (Р < 0.05), while the influence of age as well as the interaction of the two examined factors had no significant effect. The highest correlation among all investigated factors was found between surface area and egg volume.