Phenotypic Correlations among Body Weight, External and Internal Egg Quality Traits of Pearl and Black Strains of Guinea Fowl in a Humid Tropical Environment

Data on 272 eggs from Pearl (175 eggs) and Black (97 eggs) strains of laying guinea fowl hens were used to estimate phenotypic correlations (rp) between external egg quality traits and body weight of the hens as well as among the external egg traits themselves. The rp for these traits were estimated for 2, 4, 6 and 8 weeks. A random sample of 48 (Pearl) and 32 (Black) eggs, respectively were used to estimate the rp among the internal egg quality traits. The rp between body weight and external egg quality traits were significant at weeks 6 and 8 and ranged from 0.32 – 0.60 for Pearl and 0.32 – 0.68 for Black. Egg weight (EWGT) had a significant (P < 0.05; P < 0.01) rp with all the external traits in all the weeks for both strains except with egg shape index in week 6. The rp values range between 0.60 in week 8 to 0.94 in week 2 (Pearl) and 0.75 in weeks 4 and 6 to 0.89 in week 2 (Black). For the internal egg quality traits, Yolk weight was moderately (P < 0.05) correlated with egg mass and yolk diameter. Yolk height had a high correlation with yolk index and moderate relationships with albumen diameter, albumen height and albumen index. The results indicate that body weight influences external egg quality traits. Egg width and egg length are good estimators of EWGT of both strains considered. The positive correlations obtained among the traits studied indicate that they can be improved phenotypically through selection.