Comparison of live weight and body measurements of broiler Strains using Bartlett Factor Scores in Multiple Regression

Abstract

In order to compare live weight and body conformation of Arbor Acres (AA) and Annak (AN) broilers under same management and environment, the body weight and body dimensions of a population of one hundred each of Arbor Acres and Annak broilers were collected in a 56-day trial in Ibadan, Nigeria. Eight zoometric measurements namely Live weight (g), Abdominal Circumference, Abdominal length, Breast width, leg length, Height, Wing length and Thigh circumference (all in cm) were recorded for the study. Descriptive statistics, Bartlett Factor scores in multiple linear regression procedure with stepwise method of SPSS Version 17 were employed to compare body parameters of strains. Results indicated that Arbor Acres was heavier by 23.5%, and possessed wider breast by 4.9% than Annak strain at 8 weeks. Regressed normal equations had high Variance Inflation Factor (VIF) values indicating multi-collinearity among independent variables, thus reducing its predictive ability. The loading structure revealed basic differences in body conformation structure between AA (Body and Thigh Factors) and AN (Breast and Height Factors) strain and for the mixed data of both broilers as an index for broilers generally (Thigh/Breast and Body Factors). Bartlett factor scores in multiple linear regression equations yielded highly significant comparative equations with p<0.0001; and intercept of 825.51, 788.69 and 807.10 indicating differences in growth of Arbor Acres, Annak and for mixed population of both strains of broilers.