CDCB and USDA AGIL are updating the way type trait reliabilities are calculated on all non-Holstein breeds. Historically, while PTAs for type evaluations have been derived from a multiple-trait model, reliabilities were still calculated as in a single trait model. With the growing volume of appraisal data, AGIL has recommended aligning the process so that both PTAs and reliabilities follow the multiple-trait methodology.
As a consequence of this change, traditional PTAs will remain unchanged, but reliabilities for most traits will increase. Traits with limited data will now benefit from genetic correlations with other type traits, leading to improved reliability estimates. Genomic PTAs will see a more noticeable impact, as reliability adjustments affect SNP solutions and weighting factors used in final calculations. The impact will be variable across traits, as it is linked to the amount of change in the reliability. Final Score (PTAT) will be the least affected trait across all breeds, as it’s considered an uncorrelated trait.
Be the first to comment