GMACE allows all available GEBVs from all countries, and for all bulls, to be used as input data. Where GEBVs are not available, MACE EBV data are used.
For each animal, a set of Mendelian Sampling (MS) mixed-model equations are set up:
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When GEBVs are available:
MS are calculated as [GEBV – MACE PA] -
When GEBVs are not available:
MS are calculated as [MACE – MACE PA]
where PA denotes parent average.
Correlations between countries used in GMACE are the same ones as estimated in MACE therefore, National GEBV’s will be required to be from the same model and on the same base and scale as the national EBVs of proven bulls provided for MACE.
A country can therefore only participate with their GEBVs data in GMACE for the same traits as they participate with in MACE.
Like MACE, GMACE would also account for the possibility of animals re-ranking between certain countries. This occurs when animals perform better in certain environments than they do in others or when genetic evaluation methods differ between countries. For this reason, a separate set of results is calculated for every participating country. A separate list of International genomic breeding values for all traits and sires evaluated is provided to each member country, expressed in their own units and relative to their own base group of animals.
Although no specific fee model is required to participate in GMACE, GEBV-test needs to be completed and passed to participate in GMACE. The fee for GEBV-test is calculated as a 15% of the MACE Production fee.