|
Comparing
Breeding Values |
Peter Speers (Simmental Australia)
Question:
Do the Australasian EBVs of Imported Sires match their North American EPDs?
In SIMMENTAL BREEDPLAN, imported
sires receive EBVs calculated from their Australian and New Zealand born
progeny. Many of these sires also have EPDs calculated in the larger
North American genetic evaluation
(USA and Canadian progeny).
Direct comparisons of EBVs and EPDs are difficult as the traits vary slightly, are measured in kgs or lbs, and the percentile tables vary based on each country's genetic populations.
To assess how well each sire's the Breedplan EBVs and the North American EPDs rank these sires, a useful approach is to compare where the sire fits in the Percentile Table for comparable traits in each system.
This can be further simplified by assigning a "Percentile Code" (A to F) to assign where a sire fits in each evaluation system's percentile table for each trait.
| Code | Percentile | |
|
A |
Top 5% |
|
|
B |
6% to 10% |
|
|
C |
11% to 50% |
|
|
D |
51% to 70% |
|
|
E |
71% to 95% |
|
|
F |
Bottom 5% |
|
|
#N/A |
EBV or EPD not available |
A sample of sires commonly used in both Australasia and North America was compared using this approach.
Click Here to View Detailed Results
Results Summary
There was a very close correlation for most sires based on this Percentile band comparison.
For most sires, and for most of
their traits, their percentile code was the same (eg A and A)
or a close fit (eg A and C). This was especially true for the weight traits.
Some discrepancies did occur, (eg A and E) - mainly in the Calving Ease and Carcase traits, where the method of calculation varies between the two evaluation systems. The nus did occur, (eg A and E) - mainly in the Calving Ease and Carcase traits, where the method of calculation varies between the two evaluation systems. The number of analysed progeny in each country could also contribute to these discrepancies.
These discrepancies are highlighted in colour in the Results Table.
In summary, BREEDPLAN is producing genetic breeding values for imported sires with rankings within the Australasian Simmental population that closely match their rankings within the North American population.