From AngusPRO Magazine 2025
Angus Australia publishes a range of selection indexes to cover the many scenarios in which Angus genetics are utilised across Australia and New Zealand. This is in line with the ‘Angus for Every System’ vision for Angus Australia.
Selection Indexes, in the context of livestock genetic evaluation, aid in the selection of breeding animals where there are several traits of economic or functional importance by providing an overall “score” of an animal’s genetic value. They are derived for a specific breeding system and are calculated based on weightings placed on individual traits that are deemed to be important for that system, usually based on a bio-economic model.
As part of the 2024 TACE Enhancements, Angus Australia included an additional Selection Index for the Angus on Dairy production system.
Key Points:
• Angus Australia is now publishing an Angus on Diary (AOD) Research Index.
• The AOD Index has been initially released as a Research Index for further Industry consultation.
• The AOD Index can be accessed via angus.tech database search or a quarterly Sire Report.
Angus Australia has been interacting with the Australian dairy sector to gauge interest in providing genetic information on Angus animals tailored for the Beef on Dairy supply chain. As a result of the strong interest, Angus Australia developed the Angus on Dairy Research Index. Coupled with feedback from the dairy sector, the development was undertaken in collaboration with the Animal Genetic and Breeding Unit (AGBU) via the BREEDPLAN pipeline. This development specifically utilised the BreedOBJECT software.
The Angus on Dairy Research Index ($AOD) is designed for situations where Angus bulls are being used as a terminal sire over milking dairy cows, and all progeny, both male and female, are slaughtered. It focuses on calving ease, growth, carcase yield and eating quality. Daughters are not retained for breeding and therefore no emphasis is given to fertility or maternal traits.
Figure 6 (below) shows the traits that are considered in the $AOD Research Index, and how much they contribute to the overall balance of the index. The larger the segment, the greater the impact on the selection index.
Figure 7 (below) shows the selection advantage if animals are selected using the $AOD Index.
The selection advantage is calculated by ranking well used sires within the Angus breed on the $AOD index and comparing the average EBVs of the sires in the highest 10% with the average EBVs of all sires from which they were selected. For example, the sires ranked in the highest 10% based on the $AOD index had a 1.1kg lighter birthweight EBV and a 13.4kg higher 400 Day Weight EBV than the average EBVs of the sires from which they were selected.
The selection advantage is indicative of the relativity of response that will occur in individual traits if selection is based on the $AOD index. The actual response that is observed will vary depending on the features of the individual breeding program.
The Angus on Dairy Research Index is accessible from the angus.tech database search on all animals involved in TACE. It will be published in the same location as the current selection indexes (i.e. customised results layout, selection indexes tab).
Animals can also be searched for or sorted on the Angus on Dairy Index, like the other EBVs, RBV and selection indexes. A specific Angus on Dairy Research Index sire report will also be published four times per year, in line with the publication of the Angus Sire Summary.