Incorporation of external GEBV in the Dutch-Flemish dairy genetic evaluation

Abstract

Incorporation of external breeding values in an evaluation is a convenient way to increase the information underlying the breeding values from a national evaluation. This provides improved estimates of breeding values of animals with mostly or wholly foreign pedigrees. In genomic analyses external breeding values can be used to increase the reference population. In this paper we present the approach to incorporating foreign or external breeding values taken for the Dutch-Flemish genetic evaluation. It consists of 1) deregression of external breeding values, removing national information to arrive at the deregressed proof containing foreign information only and 2) transformation of the deregressed proof to pseudo-observation records that can be used as ‘own observations’ in the routine evaluation. Solutions are presented for linear single animal effects models, correlated animal effects models and random regression models. Results are shown of a validating procedure in a random regression test day model for milk production.