HERITABILITIES AND GENETIC AND PHENOTYPIC CORRELATIONS OF EGG QUALITY TRAITS IN KHAZAK LAYERS.

The aim of this study was to investigate the genetic and phenotypic correlations of egg quality traits in Khazak chicken. Albumen height (AH), albumen weight (AW), eggshell color (ESC), yolk color (YC), eggshell index, long length of egg (ELL), short length of egg (ESL), eggshell weight (ESW), egg weight (EW), Haugh units, and yolk weight (YW) were measured in 201 eggs collected 6 d sequentially from 85 Khazak layers caged individually. The ASReml was applied to estimate heritabilities and genotypic and phenotypic correlations for these egg quality traits. Heritabilities of AH, AW, ESC, YC, eggshell index, ELL, ESL, ESW, EW, Haugh units, and YW were 0.42, 0.61, 0.15, 0.19, 0.30, 0.36, 0.49, 0.54, 0.50, 0.46, and 0.32, respectively. The genetic correlations between EW and AW, YW, and ESW were high ranging from 0.78 to 0.93, whereas those for ESC with YW were low -0.89. Thus although heritabilities for these traits were moderate to high, genetic correlations with EW were high, suggesting a major relationship between EW and ESW as well as internal egg quality in Khazak layers. [ABSTRACT FROM AUTHOR]