The main changes to the economic breeding index (EBI) over the last 12 months have been an increase in the number of animals in the genomic training population and a cap on the amount of genomics that can be used to formulate an animal’s EBI.

These changes were made in a bid to increase the accuracy of a genomic proof. The result was that the EBI of the youngest genomic bulls reduced after the changes were made.

The active bull list based on the March 2021 evaluation is printed on page 48. Once again, genomically selected bulls dominate the list.

However, the average EBI of the top bulls has dropped significantly from 2020. Last year, the average EBI of the top 10 bulls on the list was €342, whereas the top 10 bulls this year have an average of €308 EBI.

These top 10 bulls all have a genomic/parent average proof and have an average reliability of 60%.

Genomic bulls have higher EBIs but lower reliabilities

There are nine daughter-proven bulls in the active bull list this spring and these have an average EBI of €256 and an average reliability of 81%.

Genomic bulls have higher EBIs but lower reliabilities whereas daughter-proven bulls have a lower EBI but higher reliability and, in most cases, that reliability is only available on milk data, not fertility.

Over the last six months, the ICBF has been meeting with discussion groups for one-to-one sessions where the group’s performance figures and breeding data was discussed. In total, the ICBF has carried out 50 meetings with discussion groups and feedback on the meetings has been very positive.

Data presented by the ICBF at these meetings clearly shows that milk-producing daughters of genomic sires have a higher EBI than daughters of proven sires to the tune of about €25 in EBI terms on average over the last five years.

ICBF data shows that the rate of gain in EBI between daughters of genomic and proven bulls is more or less the same

Andrew Cromie from ICBF says this should come as no surprise as genomically selected bulls are younger and so have a higher EBI. He says using one year of genomically selected bulls is equivalent to three or four years of genetic gain with daughter-proven bulls.

ICBF data shows that the rate of gain in EBI between daughters of genomic and proven bulls is more or less the same. It’s just that genomic bulls are at a higher level.

Should the type of proof be a consideration for farmers picking bulls this spring? The answer to that question is yes, because if using genomic bulls you need to follow strict guidelines around the number of bulls being used and the percentage of matings to each bull.

More information

This is to avoid the scenario whereby a significant number of cows are put in calf to a small number of genomic bulls. If it happens that the bull’s EBI drops as more information on that bull becomes available, then their daughter’s EBI will also drop. This will have a much greater impact on the EBI of the crop of heifer calves than if a large and evenly spread out team of bulls was used.

For example, the EBI of the top three bulls in the 2020 active bull list dropped by an average of €79 when compared to the 2021 list. This highlights the importance of using a large team of bulls when picking unproven bulls.

If a farmer decides to only use daughter proven bulls then they will have to accept having a lower EBI herd. With just nine daughter-proven bulls on the 2021 active bull list the options are fairly limited.

The main risk is that of calving difficulty as these bulls have no calving proof whereas those on the active bull list have

There are two other options beyond just using the active bull list. The first is to use Gene Ireland bulls. These are the highest EBI bulls available as they are generally 2020-born bulls. However, there are greater risks with these bulls compared to the young bulls on the active bull list. The main risk is that of calving difficulty as these bulls have no calving proof whereas those on the active bull list have.

Another risk is to do with semen quality. There was controversy up to recently over the breeding performance of Cloonigney Canning, a young bull whose semen passed quality control measures but whose in-field performance was remarkably poor.

Every farmer should use some Gene Ireland straws to maximise EBI gain

These are risks associated with test bulls and so farmers are restricted to using just seven straws of each Gene Ireland bull. Every farmer should use some Gene Ireland straws to maximise EBI gain and to help advance the national breeding programme.

Crossbreeding

The majority of the bulls on the active bull list are Holstein Friesian, notwithstanding the fact that the highest EBI bull is Jersey crossbred.

There are two other Jersey bulls on the list and one Norwegian Red bull. This means that most Jersey or Norwegian Red bulls available in Ireland have not got an EBI high enough to make it on to the list.

However, in the context of a crossbreeding herd, there is scope to use a lower EBI alternative breed and get the benefit of hybrid vigour, which in the case of Jersey bulls adds the equivalent of at least €100 to the EBI of the offspring.

This should be factored in when deciding on what bulls to use.