Economic Breeding Index (EBI)
Two methodology improvements will be implemented to the EBI in the November 2023 genetic evaluation. These are:
- Single-Step calving evaluation
- Reduction of bias in genomic for fertility
Single-Step Calving Evaluation
In line with international best practice, the single-step evaluation method will now be applied to the calving evaluation which will help to improve the accuracy of the evaluation by better 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.
Reduction of Bias in Fertility genomic evaluations
Genomic prediction bias is unavoidable and 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 approved the implementation of updates to the dairy Economic Breeding Index (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.
Dairy Beef Index (DBI)
A new methodology will be implemented, and one new trait will be added to the Dairy Beef Index in the November 2023 genetic evaluation.
- Single-Step calving evaluation
- Addition of TB resistance trait
Single-Step Calving Evaluation
In line with international best practice, the single-step evaluation method will now be applied to the calving evaluation which will help to improve the accuracy of the evaluation by better leveraging the 2.5 million genotypes available to the evaluations. The impact of this change to the DBI will be small.
Addition of TB resistance trait
Tuberculosis (TB) will now be included in the dairy beef index. The herd incidence of bovine tuberculosis (TB) in Ireland has increased. The data used in the TB genetic evaluation includes data from herd-management-groups that have several confirmed TB reactors. The TB trait definition can be interpreted as the expected prevalence of TB infection in an animal’s progeny. The breeding values for TB typically ranges from 1 to 14%, with lower values more desirable (i.e., expect fewer TB reactors). The inclusion of TB within the DBI should help to stop the unfavourable TB genetic trends.
The November 2023 Genetic Evaluations for dairy and beef will go live on November 28th.