The MACE procedure utilises relationships among all bulls. For example a half or full brother in one country will contribute information to his brothers' proof in other countries. For bulls that have no UK daughters, the MACE system will combine the UK pedigree index together with the foreign bull's proof, which is an improvement over the current method used of direct conversion. Simultaneous analysis of information from multiple countries is therefore possible and not just for two, which was a limitation with conversions. Interbull uses information on male relatives allowing unselected sires to contribute.
Biased proofs can have large impacts.
E.g. 1 st crop sibs in both countries. Excludes older sires that may not be relevant in current population. TCS systems may have been modified. In MACE, relationships between animals are correctly accounted for. The Industry agreed MACE linears are more accurate than converted linears.