EBI values of genomic sires drop by €39 in new active bull list
The Irish Cattle Breeding Federation (ICBF) has released its new active bull list for the spring 2017 breeding season.
The breeding federation delayed the publication of the active bull list earlier this month to allow for spring 2017 calving data to be added to the equation.
And, as a result, ICBF decided to bring forward the publication of its quarterly evaluation of dairy AI bulls which was not due to be published until May of this year.
Average EBI of genomic sires falls by €39
On the back of the latest evaluation, the average EBI value of Genomic sires (GS) reduced by €39. This is equivalent to about two days in calving interval and 1% for survival.
This is based on the weighted average reduction in EBI value for the 285 GS sires that are currently available in ‘Active AI’.
The top 10 bulls on the Spring 2017 Active bull list
According to the ICBF, the impact will be seen most in bulls that have a genomic “only” proof or a genomic component to their fertility proof (blended proof).
It added that these bulls are generally the younger GS bulls – born in 2015 and 2016.
Whilst the average drop is €39, the average ranking of bulls is staying very similar (with a correlation of 95% between the new evaluation and the last official evaluation), indicating that only a very small number of bulls are re-ranking significantly.
Improvements in active bull list
According to the ICBF, the average EBI of the bulls present on the active bull list continues to improve. The latest list is €7 ahead of last year’s list – up from €222 in spring 2016 (after accounting for the base correction in August 2016) to €229 for the current listing.
The ICBF also says that the reliability of bulls will increase on the back of improvements to the genomic evaluation system.
The latest analysis, carried out by the ICBF, indicates that the average reliability increased from 60% for the spring 2016 listing to 63% for the spring 2017 active bull list.
This comes as a number of improvements were included in the 2017 active bull list, including the inclusion of two-year-old bulls on the list for the first time.
There are more accurate genomic proofs for AI sires, due to a number of improvements having being made by ICBF and Teagasc to the genomic evaluation system over the past four months.
- A 15% increase in the size of the sire reference population, against which the genomic prediction equations are generated;
- The inclusion of almost 1m more fertility records from the 2017 calving season to date;
- Updates to the genomic evaluation systems and software from which the evaluations are generated.