Predicting Future Type Proofs of Young Holstein Bulls from Pedigree Information

Abstract

First-available, age adjusted classification scores of 302,921 Holstein cows scored between September, 1967, and June, 1974, were used to compute pedigree evaluations and type proofs for sires in artificial insemination. The intensity of pedigree selection for overall type score was equivalent to that expected from truncation selection on their type performance alone of the upper 15% and 2% of normally distributed populations of males and females. Optimum weights by multiple regression for predicting sons’ type proofs from pedigree information were compared to theoretically expected weights. Empirical weights for sire and maternal grandsire information were less than theoretically expected while those associated with information from the dam were greater than expected. Empirical correlations between sons’ type proofs and pedigree information were 76% or more of their theoretically expected values. The correlation between sons’ type proofs and information from the dam was greater than expected. Selections of young bulls for progeny testing based on their pedigree evaluations for type should be effective preliminary selection although less effective than expected.