The latest update to the economic breeding index (EBI) will be available from November 28, 2023, and will see changes to the fertility sub-index.
Updating of the indexes occurs on an ongoing basis, as more information becomes available from sires.
The latest update will see the adoption of a new method for the genomic aspect of the fertility evaluation, which should reduce bias.
EBI
The EBI will see two methodology improvements implemented in the November 2023 genetic evaluation.
These are:
- Single-step calving evaluation;
- Reduction of bias in genomic for fertility.
The Irish Cattle Breeding Federation (ICBF) says in line with international best practice, the single-step evaluation method will now be applied to the calving evaluation.
This will help to improve the accuracy of the evaluation by leveraging the 2.5 million genotypes available to the evaluations.
There will be minimal visible impact to the EBI as a result of this change.
Fertility
ICBF says that genomic prediction bias is unavoidable and is a global challenge.
In Ireland, fertility is one such trait that tends to be overinflated when animals receive a genomic evaluation.
After much research, a method to improve the genomic aspect of the fertility evaluation has been identified to reduce such bias.
This improvement will see a slight reduction in the number of extreme bulls available for superior fertility.
Young bulls will be most impacted by this change, they will typically see a reduction in their fertility sub-index to the magnitude of €26.
The board of ICBF has approved the implementation of updates to the dairy EBI, following independent review, consultation with working groups and technical advisory panels.
These changes stem from several years of research involving Teagasc and ICBF, arising from industry feedback and international best practice.