MACE explained

International Genetic Evaluation Service

International Genetic Evaluations are across-country measures of genetic merit of dairy for individual traits. The International Genetic Evaluation Service provided by Interbull evaluates sires of 6 breeds and 7 trait groups (milk production, udder health, conformation, longevity, calving, female fertility and workability traits). Other traits will be included in the future.

Interbull uses a scientifically advanced method known as Multiple Across Country Evaluation (MACE) to calculate International Genetic Evaluations. More detailed information about MACE are available in the Interbull Code of Practice.

MACE has two major advantages over other methods:

1. Use of all known relationships between animals
   MACE combines information from each country using all known relationships between animals, both within and across populations.
   
   
2. Genotype by environment interactions
   MACE accounts 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. This process is demonstrated in the figure demonstrated in the figure below:

This figure shows that the International Genetic Evaluations calculated for sires from countries A and B (and their subsequent ranking’s) can be different from one country to the next.A separate list of International Genetic Evaluations 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.This provides the advantage of individual countries being able to identify those animals from around the world that will perform best under their own unique farming conditions. Currently, results are made available to member countries five times per year: three of these (April, August and December) are official results for publication, the other two (January and September) are test results which cannot be published, but can be used by countries to improve their models, methodologies and processes. Interbull results involves/comprises more than 150,000 bulls for six breed groups.

Please Note. Interbull does not rank animals in any way and only calculates breeding values on the different country scales. Member countries are responsible for ranking sires using their own breeding objectives, and publishing the results.