DHIA/Records

The increase in Net Merit $ of service sires of $105 compared to this time last year is a dramatic change. The cause appears to be from heavier use of young sires with really high genomic proofs. This past January the USDA genetic evaluation system changed to include genomic information. The way that resulting proofs were published affected the record system at DRMS Raleigh. Apparently, young sires with genomic evaluations have been treated as proven bulls in recent DHI herd summary reports. As a result, the average merit of “proven” service sires increased. I don’t think the increase is misleading, as the average bull used as a service sire in Virginia today is almost certainly quite a bit better than a year ago. But interpretation of average merit of service sires has changed. DRMS is making adjustments to put progeny tested bulls back into a separate category from bulls with genomic evaluations and no progeny. Today, many dairy farmers use genomically tested young bulls for herd improvement rather than just for progeny test purposes. This is as it should be. Reliabilities on Holstein young bulls in AI increased, from about 35% to about 65 to 70%, with addition of genomic information. Dairy farmers can identify the exceptional bulls with greater accuracy than in the past, and bulls with exceptional genomic proofs should be used more heavily as a result. In the coming months, DRMS will place genomically tested young bulls back in separate category on the Herd Summary 202. This change will let producers compare the merit of proven bulls with the genome tested young sires, and will show how much each group of bulls has been used across the herd. Genome-tested young bulls with outstanding proofs should be considered herd improvers rather than sample sires. The average merit of service sires shown in the table probably should include both categories of bulls.

DHI Notes...