After reviewing correlations between genomic test results and actual animal performance, USDA's Animal Improvement Program Laboratory scientists have revised weights used to predict genetic evaluations for genotyped animals. The end result is Holsteins, Jerseys, and Brown Swiss with DNA-only predictions will more closely reflect those with traditional evaluations which are based on actual performance and progeny results along with DNA information, if available. The changes will be implemented immediately for this spring's genetic evaluations set to be released on April 3.


As a result of these revisions, animals that have greater difference between a genomic and traditional evaluation will experience more adjustment toward the parent average. For example, genomic PTAs (predicted transmitting abilities) for the highest young Holsteins will be reduced by about 100 pounds of milk, 4 pounds of fat, 3 pounds of protein, 0.2 months productive life, 0.15 final score on type, and $20 net merit. Other Holsteins will have smaller adjustments.

Meanwhile, adjustments for the highest young Jerseys and Brown Swiss will be twice as large for yield traits when compared to Holsteins, but similar for other traits.

During these updates, reliabilities changed very little. There are no changes in the other dairy breeds because they do not have genomic test information yet.

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