Phenotypic evaluation of growth traits in two Nigerian local chicken genotypes
A study was conducted to evaluate growth traits, including body weight, body length, chest girth, leg length, shank length and shank circumference, using data obtained from 150 mixed sex birds originating from improved Nigerian local chicken (75 normal feather and 75 naked neck genotypes) of 4 – 16 weeks of age. Body weight of each genotype and at various ages was regressed on other growth traits studied. During the early growth phase (4 – 8 weeks), there were significant variations (p<0.05) between the normal feather and naked neck birds in body weight, body length, leg length and shank circumference with the normal feather having higher values. No disparity (p>0.05) was observed in the two genotypes for all traits by the 16th week of age. Strong and highly significant (p<0.001) correlation coefficients (r) were estimated between body weight and other growth traits in the normal feather (0.62 – 0.94) and naked neck (0.73 – 0.94). Apart from the 4th week of age, strong and positive correlations were obtained between body weight and the other traits (p<0.001). Significant and high coefficient of determination R2 was obtained when body weight was regressed on the other growth traits in the normal feather and naked neck population (0.89 and 0.90 respectively). The R2 was also high (>0.77) for all ages except at 4 weeks of age (0.04), indicating that most of these traits could be used to forecast body weight precisely at various ages.
Keywords: Local chicken, Normal feather, Naked neck, Body weight, Growth traits, Linear model