Genomic based breeding values are now in active use in Australia. The following information will help you use ABV(g)s when making bull selection decisions.
ABV(g) is the new term to express genomic based breeding values. The same principles that apply to current ABVs are used in the presentation of ABV(g)s to make it easier for breeders and industry to use them. This means ABV(g)s are expressed in the same way and on the same base as ABVs and are directly comparable with each other.
In the presentation of ABV(g)s you are likely to see
Bulls that have been genomically tested but do not have sufficient milking daughters in Australia will have an ABV(g) for each trait as outlined in Table 1. When these bulls become ‘proven’ through the addition of information from enough milking daughters, then they will receive a publishable ABV.
Table 1 A summary of ABVs, ABV(i)s and ABV(g)s
Breeding values based on genomic and pedigree data.
|Interbull breeding values for bulls proven overseas
Breeding values with no Australian daughter performance information.
Breeding values utilising Australian milking daughter information.
Meet publishable requirements for production, type and workability. breeding values.
All bulls that have been genomically tested are labelled with a ‘g’ on information supplied by ADHIS. Genomic data is unlikely to influence the ABV of a well proven bull with thousands of daughters in Australia, however it may have an impact on newly proven first-crop bulls. In either case, the inclusion of genomic data is indicated on material supplied by ADHIS.
The ‘Displayabull’ tool on the ADHIS website is a handy search tool to find ABVs and ABV(i)s for all bulls marketed in Australia. Bulls with ABV(g)s are included in this tool. By using this independent source of data, you can be assured of viewing the most accurate and reliable information available on the group of bulls you are considering for use in your herd.
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Right now, you will open catalogues and see genomic based breeding values from overseas countries. These breeding values are an estimate of the genetic merit in their country of origin but are less accurate in predicting the bull’s performance in Australia.
The Australian genomic evaluation system is generated from actual daughter performance data in Australia providing a better indicator of a bull’s performance in this country.
Australia’s genomic evaluation system is an open system meaning that all AB companies have the opportunity to genomically test bulls in Australia. To find the best estimate of a bull’s performance in Australia – look for an ABV(g).
It’s a team game
When selecting bulls for your herd, it is a good idea to manage risk by including a number of bulls in your team. The results breeders can expect from different bulls depends to some extent on the bull’s reliability.
Reliability is a measure of confidence in an Australian Breeding Value (ABV). The reliability of a bull’s ABV for a particular trait indicates the chance the breeding value may change in the future – up or down. A bull’s reliability improves over time, as more information about the performance of his daughters becomes available from herd testing results, new classifications and other data sources.
Bulls with ABV(g)s will initially have less reliability than a proven bull. However there’s still a good case for using these younger bulls: they represent the most recent genetics so have greater potential to contribute to genetic gain in your herd. What’s important is to manage the risk of underperforming bulls by using a team of bulls.
More to come
Genomics is new. It’s exciting and it’s continually improving. Further details will continue to be published in the months (and years) to come.
For more information, contact the ADHIS team on 03 8621 4240 or e-mail email@example.com.