Browsing by Author "Kuje, D."

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    Principal Components as Measures of Size and Shape in Nigerian Indigenous Chickens
    (Department of Animal Science, Nasarawa State University, Keffi., 2009-01-14) Yakubu, Abdulmojeed; Kuje, D.; Okpeku, M.
    The study aimed at describing objectively the interdependence among the morphological traits of Nigerian indigenous chickens and to predict body weight from their orthogonal body shape characters using principal component factor analysis. Body weight and eight body measurements namely, comb height, comb length, beak length, body length, neck length, shank length, chest circumference, and thigh circumference were measured on 238 randomly selected adult chickens of three genetic groups. The birds were extensively managed in Nasarawa State, north central Nigeria. General linear model was used to study genotype and sex effects. Frizzled birds had higher beak length and lower neck length compared to their normal feathered and naked neck counterparts. Sexual dimorphism was observed in all the traits with higher values recorded for males. Phenotypic correlations among body weight and biometric traits were positive and highly significant (r = 0.56-0.91, 0.61-0.91 and 0.55-0.96; P<0.01 for normal feathered, naked neck and frizzled chickens respectively). In factor solution of the principal component analysis, with varimax rotation of the transformation matrix, three factors were identified in each of the genetic group (ratio of variance = 87.84, 90.60 and 89.20 for normal feathered, naked neck and frizzled chickens respectively). The first factor in each case accounted for the greatest percentage of the total variation, and was termed general size. The subsequent factors (indices of body shape) presented patterns of variation independent of general size. The principal component based regression models, which are preferable for selecting animals for optimal balance, accounted for 85, 84 and 87% of the variation in the body weight of normal feathered, naked neck and frizzled chickens respectively.