Variation between and within birds in the estimation of the metabolizable energy content of diets for laying hens

Abstract

SUMMARYThree experiments were performed in which variation in metabolizable energy (M.E.) determinations was studied using a total of 137 laying hens. Consistent breed differences in classical M.E. estimates were found, and there were statistically significant differences between pullets within strains. Estimates were obtained of the within-bird variation in classical M.E. determinations and, from the estimated variance components, standard errors of the mean classical M.E. value were predicted for determinations using various numbers of pullets of one breed and various numbers of measurements per pullet.