Changes to active bull list explained

The ICBF has just this week released the new active dairy bull list and genomic sire proofs have adjusted downwards as more daughter-proven information is now available. It is fair to say the timing of changes and publication have angered farmers and the AI services sector. ICBF contends it is better to be up front on changes and release updated information while there is still the chance for the farmer to make the right decision. ICBF chief executive Sean Coughlan answers the key questions

What has changed?

The listing contains a number of notable improvements compared with previous years. These include: the inclusion of 2015-born bulls on the listing for the first time, and more accurate genomic proofs for AI sires. The improvements include 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 and updates to the genomic evaluation systems and software from which the evaluations are generated. The board of ICBF recently decided to implement these planned changes now, in advance of the forthcoming breeding season.

What is the impact on the active bull list?

The average EBI of the ICBF active bull list continues to improve, with the latest listing being €7 ahead of last year’s listing, up from €222 in spring 2016 (after accounting for the base correction in August 2016), to €229 for the current listing. The list is dominated by young genomically selected (GS) bulls (68/75).

Will there be changes in the proofs for bulls as a result of the genomic and data updates?

Yes there will be changes, with on average these young GS bulls reduced by some €39 in EBI value (equivalent to about two days in calving interval CI 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. Some bulls will drop more and others less than this average figure, depending primarily on how the sires of these young GS bulls are performing on farms. Only a small number of bulls are re-ranking significantly.

What will happen to reliability?

The reliability of bulls will increase as a result of the above improvements in the genomic evaluation system, with the latest analysis indicating an increase in average reliability from 60% for spring 2016 listing, up to 63% for bulls on the spring 2017 listing.

Should I continue to use genomic bulls, or should I now be considering using daughter-proven bulls?

On average a group of genomic bulls will still be better than any daughter-proven bull when it comes to delivering production and fertility.

For example, the current average EBI for a team of the top five genomic bulls is still some €53 ahead of the best daughter-proven bull available on the new ICBF active bull list.

This is also apparent from research trials. So the simple message to farmers is yes, they should still use the genomic bulls, but they should use them in teams, ie a minimum of five bulls used equally across the herd, so as to minimise the potential impact of any EBI changes to bulls (and their herd) in the future.

Are we likely to see more changes to the proofs for GS sires in the future?

Improvements to genetic evaluations are an ongoing process. Reasons for proof changes include: the addition of new data, the addition of new traits, changes to the economic values of traits over time and improvements to systems and software, such as outlined above.

The main aim of these changes is to improve the reliability of animals and ultimately help farmers breed the most profitable cows for the future. This is the ultimate goal of ICBF and therefore reflects completely the decision taken recently by the board of ICBF to bring forward the May evaluation run to March 2017, and in doing so, ensure farmers and industry have the best information on which to make their breeding decisions this spring.