Comparison of alternative strategies for an international genetic evaluation of beef cattle breeds

Although the Limousin breed has been developing in several countries for the last four decades, the genetic evaluation of seed stock is usually performed within country. However some foreign cattle are simultaneously evaluated with the French animals (Italy, Luxembourg, Hungary) or with the Australian animals (New Zealand). Breeders may seek to compare their domestic to overseas seed stock in order to enlarge the choice of animals that better fit their own selection objectives. In collaboration with the Irish Cattle Breeding Federation (Ireland), the Meat and Livestock Commission (UK), the Institut de l’Elevage (France) and INTERBULL sub-committee of ICAR, a research program was conducted at INRA (SGQA, France) with the purpose of developing an European genetic evaluation in British, French and Irish Charolais and Limousin breeds (Renand et al., 2003) and at UNE (AGBU, Australia) with the aim of comparing the different strategies for such an international genetic evaluation of beef cattle breeds. It is this second part of the research program which is reported here and which relates to the benefit of using a complex model (which treats raw data in each country as correlated trait) versus a simpler model (that includes only the heterogeneity of the environment and genetic variances) on raw data or on de-regressed proofs. Population data