Olcastletown Mojo has retained his top spot on the 2026 active bull list published by ICBF. With an EBI of €285, he has the highest EBI of all bulls eligible for inclusion in the active bull list. The criteria to get on to this list is two-fold. Firstly, bulls must be “active” – and this essentially means that there is semen available from them. Secondly, they must have a calving proof, so there must be a minimum number of calving records in the database before they can make it onto the list.

There are higher EBI bulls available, but they don’t yet have a calving proof, hence they are not included in this table. For example, The NCBC bull Faha Connick (FR2904) has an EBI of €339, €54 higher than Mojo, but he does not appear on the list. Born this time last year, Connick does not have a calving proof and is unlikely to have one until probably the March evaluation in 2027.

Essentially, the active bull list is a list of established bulls, not necessarily the highest EBI bulls in the country. However, it’s important to note that these young bulls with the higher EBIs come with a health warning – in that they generally don’t have any field fertility data and, as previously mentioned, they don’t have a calving proof.

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The lack of field fertility data is concerning because. despite passing all possible laboratory tests on semen quality and motility, there are sometimes problem semen in terms of getting cows in-calf. We have seen this previously with some high-profile bulls which proved to be highly infertile, despite passing lab tests.

So, there is a health warning attached to using the young bulls with the highest EBIs that are not on this list. Overcoming these potential issues involves using a larger team of bulls, so that if one bull has an issue, it will only affect a relatively small proportion of the herd.

Of course, the reasons for using larger teams of bulls is not just confined to the youngest bulls, it is also necessary when using all bulls, even including daughter-proven bulls. In the active bull list of the top 75 bulls, 53 are genomically selected, meaning progeny performance is not part of their proof.

Of the 22 that are daughter-proven, the daughter proof only relates to their milk figures, not fertility data. The fertility sub-index will still be based on a blend of parental average and genomics.

Therefore, larger teams of bulls should be used to overcome the inevitable volatility in EBI, when they become daughter-proven. To be fair, the sector has embraced the use of larger bull teams and tools such as the Sire Advice programme on ICBF Herdplus make assigning bulls to cows much easier compared to manually selecting matings.

The result of using larger bull teams is more stability in the EBI of the calf crop and this follows through to subsequent generations.

Changes

Of course, there have been substantial changes made to the EBI since this time last year with the base population change and changes to some of the economic values.

The base change has meant that the EBI of all animals has dropped. Eagle-eyed readers will know that this time last year, Olcastletown Mojo had an EBI of €375, which is €90 higher than his current EBI.

This is not necessarily because his EBI dropped as most of the reduction in the EBI is as a result of the base change. This means that the group of animals that EBI is being compared against moved from born in 2005 to born in 2015.

Other differences include changes to the maintenance sub-index whereby the growing costs of rearing heifers has moved from beef to maintenance.

ICBF has a useful maintenance ready reckoner calculator on its website to work out the expected liveweight based on the maintenance sub-index.