PHENOTYPIC CORRELATIONS BETWEEN EGG QUALITY TRAITS OF THE JAPANESE QUAIL IN A SEMI-ARID AREA OF NIGERIA

Abstract

Phenotypic correlations between egg quality traits in Japanese quail were studied at the poultry unit of the livestock teaching and research farm. University of Maiduguri, Maiduguri. Two hundred and twenty (220) eggs were collected from 110 quail hens at 20 weeks of age. The values related to egg weight, shell weight, shell ratio, average shell thickness, egg shape index, egg surface area and shell weight per unit surface area were 9.77 g. 0.90 g. 9.29 %, 0.217 mm, 83.0 %, 21.98 cm2 and 44.30 mg/cm2, respectively; while weight, height, index, and ratio and weight, height, diameter and ratio and Haugh Unit were 5.45 g. 3.95 cm, 6.58 %, 55.72 %, 3.41 g. 1.00 cm, 2.48 cm, 34.98 % and 87.77 %, respectively. Egg weight had positive correlations with both external and internal quality traits indicating that it may be the best trait for improving others. Most internal quality traits had negative correlations with shell ratio, implying that selection for internal quality traits of quail eggs could result in low shell quality. Selection to improve albumen weight will have an antagonistic effect on yolk ratio because negative correlation was observed between them. Shell ratio had negative correlations with some albumen qualities whereas it was positive with yolk quality traits implying that eggs selected for albumen quality may have poor shell quality. However, the quality may be improved if some yolk traits are considered in such selections.