Evaluation of different egg quality traits and interpretation of their mode of inheritance in White Leghorns

Aim: The experiment was carried out to evaluate different external and internal egg quality traits and to figure out their mode of inheritance from a set of hierarchically classified data. Materials and Methods: The data collected from 548 progenies (1 egg from each progeny) of 282 dams mated to 47 sires (1 sire mated to 6 dams) of a White Leghorn flock were used in the present study. Phenotypic means and their standard errors were calculated for all the quality traits. Heritabilities were estimated for these traits separately from "sire," "dam" and "sire+dam" (full-sib) components of variance using Statistical Package for Social Sciences-17 program. Results: External quality traits such as; egg weight, length, width, shape index, surface area, shell weight, shell thickness, shell ratio, and internal quality traits such as; length, width, height, and weight of albumen and yolk, albumen index, albumen ratio, Haugh unit (H.U.), yolk diameter, yolk index, yolk ratio, and yolk albumen ratio were measured in 548 eggs of the experimental White Leghorn flock. The eggs were found to have optimum weight (57.78±0.20 g), shape index (73.53±0.18) and shell characteristics (6 g, 0.32 mm) as per its genetic potential. Higher values for albumen height (8.41±0.04) mm and H.U. (92.00±0.19) are attributable to the freshness of eggs and proper age of hens. Heritability estimates from "sire" component of variance were higher than "dam" and "sire+dam" components for the traits like egg weight, length, width, shape index, surface area, albumen width, albumen index, H.U., yolk width, yolk height, yolk weight, and yolk index whereas for rest of the traits the values estimated from "dam" component were higher. Estimates from "sire+dam" component were intermediate to the estimates derived from "sire" and "dam" components. Conclusion: The heritability estimates from different egg quality traits were moderate to high. Since most of the traits have high heritability values, these traits can be improved by mass selection