A general approach for international genetic evaluations robust to inconsistencies of genetic trends in national evaluations.

Abstract

This paper is a contribution from the PROTEJE project. It presents an approach which makes uses in a sire model of annual information (= average daughter yield deviations per year of performance and lactation number) for each sire. It is shown that with a suitable sire model (including a year x country effect, a lactation x country effect and a within country regression on age of the sire when his daughters are born), the genetic parameters and the sire solutions obtained are robust to overor under-estimation of genetic trend in the national models. The approach has other benefits: validation of genetic trends is no longer critical (although obviously desirable), deregression becomes obsolete. An extension to categorical or survival traits is briefly described and a general strategy for the computation of equivalent daughter contributions and daughter yield deviations and their validation is proposed.