The genetics of the U.S. dairy herd has improved incredibly over the years. Now, with the help of technology, we can record more data that helps us adjust genetic evaluations more accordingly. To keep accurate tabs on the ever-changing production traits, once every five years, genetic bases are adjusted to complement the improvement of herdmates, comparing current genetics to the average animal born in 2020. In a University of Wisconsin-Madison extension article, dairy educator Matthew Lippert highlighted changes that we will see come the April triannual evaluations.

Genetic herd estimates are based upon DHI records, herd health and fertility data, classification scores, and genomic markers from nearly 10 million dairy animals in the database. On the flipside, some of these traits have only been added recently, meaning not all traits have the same data backing as some that have been included in the base for years. These traits included in the indexes are weighted based upon economic importance.

The main drivers of dairy farm economics include butterfat and protein pricing changes. “The April indexes for lifetime net merit (NM$), lifetime cheese merit (CM$), lifetime fluid merit (FM$), and lifetime grazing merit (GM$) will be updated to account for the change. In addition, the formulas have been updated to account for changes in the economics impacting dairy farms,” Lippert explained.

Some traits complement, offset, and negatively affect each other. By understanding these traits’ effects in the selection index, genetic progress can be made. The new base changes will set the breed averages to zero. “This does not mean our selection system was inaccurate; it means that it has been rescaled due to rapid genetic progress and improved accuracy, an indicator of the success of our nation dairy cattle selection scheme,” he said. While the estimates in the table below are approximate of the lowering predicted transmitting ability (PTA), they may change slightly once set calculations are unveiled in April.

Source: Council on Dairy Cattle Breeding; USDA-ARS Animal Genomics and Improvement Laboratory