Genetic and Environmental Factors in Dairy Sire Evaluation. III. Influence of Environmental and Other Extraneous Correlations Among the Daughters

The practice of regressing dairy sire proofs for the numbers of daughters included and for the average correlation among those daughters has been gaining wide acceptance in recent years. However, the contributions of environmental and other extraneous correlations to the regression factors being used have been generally neglected. Justification for this has been based largely on the assumption that, when deviation records are used, the effects of these residual correlations in artificial insemination (AI) bull proofs are of no practical significance.