Abstract

The November 2001 official international genetic evaluation of dairy bulls for production traits has seen 25 countries sending and receiving data from Interbull. The current method used for international comparisons of dairy bulls was developed by Schaeffer in 1993 and it is known as Multi-trait Across Country Evaluation (MACE). Bull proofs computed at the national level are provided to Interbull every four months. They are de-regressed and used as elementary observations in a multiple trait BLUP sire model considering production in different countries as different traits. At the end of the process, each country receives a list of EBVs on its own scale for all bulls evaluated in any of the participating countries. Over time, the method has been improved but has been found highly sensitive to changes in sire variance (within country as well as over time) to quality of national proofs and to changes in genetic correlations. As the number of Interbull countries is growing, the precise estimation of the about 350 genetic correlations for each trait between countries for Holsteins is becoming a  formidable task. The present approach only evaluates bulls and with the increasing international exchange of female embryos and live cows, an international genetic evaluation of elite females is highly desirable. In order to overcome potential biases resulting from the partial use of basic information, (summarised in the national sire proofs), several attempts to run a global animal model (GAM) using raw data (i.e. records and pedigree on all cows within each population and their related sires) have been made (Weigel et al., 1999, 2001). 

F. Canavesi, Didier Boichard, Vincent Ducrocq, Nicolas Gengler, Gerben de Jong, Z. Liu

Proceedings of the World Congress on Genetics Applied to Livestock Production, Volume 2002. Session 1, , 1.59, 2002
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