Phenotypic Correlations of Body Weight and Linear Body Traits in Heavy, Medium and Low Body Weight Lines of Sigmond Strain of Japanese quails in Humid Rainforest Zone of Nigeria
Data on 126 Sigmond strain of Japanese quail chicks consisting of 42 each of heavy, medium and low body weight lines were used to estimate phenotypic correlations (rp ) among body weight (BWT) and linear body traits at 2, 4 and 6 weeks of age. The linear body traits considered were breast girth (BG), shank length (SL), keel length (KL) and wing length (WL). The rp between BWT and the linear traits were strong, positive and significant (P < 0.001; P < p 0.01) at all the ages for the heavy and medium lines. The values ranged between 0.678 – 0.850 (heavy), 0.630 – 0.844 (medium) at age 2, 0.631 – 0.827 (heavy), 0.561 – 0.730 (medium) at week 4 and 0.676 – 0.824 (heavy), 0.561 – 0.730 (medium) at week 6. Significant correlations were only observed between BWT and BG and SL (week 2 and 4) and BWT and BG, SL and KL (week 6) for the low line. The phenotypic associations observed among the linear body traits were also strong, positive and significant for the heavy and medium lines at week 2, 4 and 6. Significant correlations were noted for the low line only between BG and KL (0.508) and KL and WL (0.803) at week 2, KL and WL (0.520) at age 4 and BG and SL (0.647) and BG and KL (0.928) at week 6. The results obtained in this study indicates that heavier and/or medium-sized quails would yield higher proportions of BG, SL, KL and WL and that these traits could be used to phenotypically improve BWT in Japanese quails. The all positive rp associations among the linear traits also indicate that phenotypic selection in any one trait would lead to improvement of their associating traits.
Keywords: Body weight, linear body traits, phenotypic correlation, Japanese quail