Prediction of Internal Quality Characteristics by Regression Equations Using External Quality Characteristics of Egg in Cream Coloured Laying Hens

Objective: This study was conducted to predict egg weight, eggshell weight, shell thickness, eggshell surface area, egg shape index, egg yolk height, egg yolk diameter, egg yolk, egg yolk weight, albumen weight using various egg characteristics as independent variables. Materials and Methods: In this study, Lohmann Sandy eggs obtained from a commercial free range egg production enterprise in Ordu province were used. The eggs used in this study were collected at 24, 28, 32, 36, 40, 44, 48 and 52 weeks of age and calculations were made using a total of 30 eggs in each of these weeks. During the research, an electronic scale sensitive to 0.01 g was used for weighing the eggs, a caliper sensitive to 0.01 mm was used for measuring egg length, width, and yolk diameter, a flat glass-covered table was used for breaking the eggs, a tripod micrometer sensitive to 0.01 mm was used for measuring yolk and albumen height, and a micrometer sensitive to 0.01 mm was used for measuring shell thickness. In the study, regression equations were developed using eggs obtained at 24, 28, 32, 36, 40, 44, 48 and 52 weeks of age. Results: In the study, egg weight was significantly and positively correlated with egg length and egg width and the correlation values were 0.569 and 0.859 for egg length and egg width, respectively. At the same time, a high phenotypic correlation was found between egg weight and white weight (0.957) and a highly significant correlation was found between egg weight and yolk weight (0.610). A highly significant and positive correlation was found between albumen index and albumen height (0.893), while significant and negative correlation was found between albumen index and albumen width (-0.575). Conclusion: Based on the findings, the examined traits can serve as selection criteria for improving egg weight. Furthermore, the identified correlations between internal and external egg quality traits suggest that these parameters can be improved through selection.