The International Dairy Cattle breeding industry characterises itself by ever increasing competition between countries. Frozen semen and embryos are easily transportable, providing breeders with access to bulls from almost anywhere in the world. Problems arise from the fact that each country produces genetic evaluations with different units, different expressions of genetic merit and different genetic bases. Without some means of standardisation it is very difficult to make the correct selection decisions.

Procedures have been recommended and described by the International Bull Evaluation Service (INTERBULL) to convert foreign genetic evaluations to the genetic equivalents in the importing country (Philipsson et al. 1986). Previous research carried out in the UK has shown that converting foreign proofs to Improved Contemporary Comparisons (ICCs) worked well for Canada and New Zealand (Swanson et al, 1989). The change in the evaluation systems in the UK and elsewhere, to an Individual Animal Model, plus the availability of more data from more countries, were reasons to re-look at the accuracy with which the current conversion method predicts the actual PTA for milk, fat and protein within the UK.