Recording management group information is one of the most important aspects of collecting performance information.
Why are management groups important?
The performance of animals is analysed in contemporary groups to take out the influence of as many of the non-genetic effects as possible (e.g. management, nutrition, feed, year, season, injury, health status). The underlying principle is that only animals that have had an equal opportunity to perform are directly compared together within each contemporary group. If the contemporary groups are not correctly formed, the EBVs calculated will be less accurate and possibly misleading.
Most of the problems that breeders encounter in “believing” their EBVs can be traced back to incorrect contemporary grouping – either calves being fragmented into isolated groups of only one or two animals (and thereby virtually eliminating those calves from any comparison with their peers) or by not differentiating between calves who performance has been influenced by different non-genetic factors (e.g. differences in management or feeding).
Importantly, the management groups that are submitted with each set of performance information have a major influence on which animals are directly compared within each contemporary group
Assigning management groups
Specifying management group information is an important consideration when submitting any performance information. By assigning animals
into management groups, seedstock breeders are acting as “eyes” for the genetic evaluation and ensuring that only the performance for animals that have had the same opportunity to perform is directly compared together.
Animals should be assigned into different management groups in any situation where their performance has been affected by different non-genetic influences to other animals. In practical terms, animals that have been run in the same contemporary group and have had equal opportunity to perform should be grouped together.
Some examples of where animals should be recorded in separate management groups are: