IN a move towards a global genetic evaluation for structure, direct comparisons between structural soundness estimated breeding values (EBVs) of Angus animals within Australia and North America will now be possible.
Angus Australia breed development and extension manager Andrew Byrne announced during the AngusCONNECT Research and Development Spring 2020 update that from December the genetic evaluation for structural soundness will be conducted jointly with the American and Canadian Angus Associations.
This is part of the complete overhaul of Angus Australia's structural EBVs that have been routinely published since 2016, that follows considerable feedback from its membership.
The analysis will be provided by Angus Genetics Inc, and will allow for the structural scores of animals recorded across the three countries to be included for direct comparison within the one genetic evaluation.
"Australia has the biggest amount of data included in the initial round (68,366 scores compared too 39,503 from North America)," he said.
"The US haven't been at it as long, they started scoring in 2015, released research breeding values in 2018 and estimated progeny differences (EPDs) for structural soundness became an official part of their analysis in 2019."
Therefore the North American scores are mostly from recent years, while the Australian scores extend over a period of time.
A benefit to this move is the breeding values produced on a number of animals in Australia are directly comparable to the breeding values produced on North American sires.
"Looking at a North America sires to use in your breeding program, we can now take the EPD times it by two and it will give the same or equivalent EBV in Australia," Mr Byrne said.
"Likewise, divide Australian EBV by two to produce an EPD that will be directly comparable."
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The downside is the small number of scores from New Zealand that were feeding into the previous analysis won't feed into this at this stage, Mr Byrne said.
"Submission dates for structural scores will be seven days prior to the submission date for other performance data," he said.
But this isn't the only change.
The previous five structural soundness EBVs, including front feet angle, front feet claw set, rear leg angle, rear leg hind view and rear leg side view, will now be consolidated into two - an EBV for claw set and an EBV for foot angle.
The scoring system won't change, according to Mr Byrne who said front and back will still be scored separately but within the analysis only one EBV will be calculated for the trait.
While not published, the existing EBVs for rear leg hind view and rear leg side angel will be available to members on request.
A new analytical model is being introduced that will allow multiple scores per animal and structural scores of mature females to be analysed, as well as the incorporation of genomics and an adoption of a linear mode
"The scoring system remains one to nine, but only scores of five or greater will be included in the analysis," Mr Byrne said
This is because very minimal scores of one to four have been submitted.
The units in which the EBVs are published will change.
"At the moment, the EBVs are published as genetic differences in the percentage of progeny expected to have acceptable structure, all other things being equal, with higher EBVs more favourable," he said.
This has been flipped on its head, with now more negative values more desirable and the EBVs being reported in differences in score units.
"A lower breeding value indicates a lower score, or a score closer to five and more optimal structure," Mr Byrne said.
To address the low level of scoring and to make it easier for people to submit structural scores into the analysis, Angus Australia will now accept breeder collected scores alongside those from accredited independent assessors.
Producers are still encouraged to use an accredited assessor to collect scores on sale animals.
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