Genomics has transformed dairy cattle genetics and makes a deeper impact on the U.S. milk supply with each passing year.
“At one time, management factors such as improved nutrition and feeding programs, more digestible forages and grains, and enhancements in cow comfort set the pace for improvement in milk, butterfat and protein production,” says Corey Geiger, lead dairy economist at CoBank. Everything changed in 2008 when genomics — the study of DNA and comparisons to large datasets — was introduced to the U.S. dairy industry.
“Genomics created faster genetic improvement with each passing year, and these days, it plays a larger role in gains for dairy cow efficiency than the entire bundle of management factors we implement on our dairy farms,” Geiger says.
When discussing this value proposition, it’s important to point out that the dairy cow is the most studied domestic animal on the planet. That may sound like a bold statement. However, according to Geiger, when it comes to the amount of genetic information collected on dairy cows, the only other groups with larger genetic datasets among mammals are humans and lab mice.
The power of genomics is not in the DNA sample, however. “It is found in the dataset when comparing that DNA sample to the database that holds the over 100 million records collected by the Dairy Herd Improvement Association,” Geiger explains. “As years have passed, fertility, longevity and other health records added to the robustness of the datasets.”
When the first genomic evaluations were released in 2009, very few cattle were listed.
“It took seven years for the U.S. to genotype 1 million dairy animals,” Geiger says. “Then it took two more years to reach the 2 million threshold. As confidence in the system gradually grew, dairy farmers began running more tests with each successive year to continue building momentum. By March 2021, the U.S. dairy industry moved past 5 million tests, and flew past the 10 million mark in December 2024.”
Base change pinpoints impact
The Council on Dairy Cattle Breeding recently announced changes to the genetic base for dairy cattle evaluations. A base change is essentially a “rollback” on traits to keep numbers from appearing inflated, Geiger explains.
“Generally speaking, the larger the rollback, the larger the genetic gains,” he says. “In scientific terms, this means the genetic base is reset to an average cow born in 2020. For further perspective … if a genetic base change would take place in 2030, the base would be reset to the average cow born in 2025.”
In a previous era, USDA conducted genetic evaluations on dairy cattle. The federal agency implemented the first base change in 1965, and subsequent base changes took place in 1974 and 1984. Beginning in 1989, base changes began occurring roughly on five-year intervals. This year will mark the 11th such base change. In 2013, USDA passed the baton to CDCB to calculate genetic evaluations.
“In late December, the council — comprised of breed associations, bull studs, and DHIA testing groups and processing centers — announced their preliminary estimates for the rollback on predicted transmitting abilities for 13 traits,” Geiger notes. These traits include production metrics such as milk, butterfat and protein, along with health traits like somatic cell score, daughter pregnancy rate and productive life. “Given the importance to U.S. dairy processing, let’s focus on butterfat and protein.”
Record improvement for Holsteins
Holsteins led all breeds by having a 45-pound rollback on butterfat, which is an 87.5% shift from the 24-pound rollback in 2020. While not quite as large on a percentage basis, protein for Holsteins will roll back 30 pounds in the upcoming April genetics evaluations. This is a 67.5% improvement from 2015, when 18 pounds of protein were trimmed off genetic evaluations, Geiger says.
“To fully appreciate how large these genetic base changes have become in the genomic era, one simply needs to look back a few years,” he explains. “In 2015, the Holstein base rolled back butterfat by 17 pounds and a mere 9 pounds in 2010. The shift was even smaller for protein, at 17 pounds in 2015 and 6 pounds in 2010.”
There’s been a great deal of discussion in some industry circles about breed composition in this era of growing butterfat and protein production. From 2011 to 2023, U.S. milk production grew just 16.2%, while protein production expanded 22.9% and butterfat jumped 28.9%, Geiger says.
“Both butterfat and protein production stand at record highs, and 2024 will go down in the record books as the very first year that shipped milk was over 4% butterfat every month — even during summer,” he says.
With 83% of semen sales in 2023, Holsteins contributed a major share to growth in these two valuable milk components, he notes. The Jersey breed also made gains, with a 20-pound base change for butterfat and a 15-pound base change for protein projected for the upcoming April genetic evaluations.
“To some extent, genetic progress did slow somewhat in Jerseys, as these numbers are down 20% and 25%, respectively, for butterfat and protein when compared to the previous base change,” Geiger says. Back in 2020, Jerseys netted a 25-pound base change for butterfat, 1 pound higher than Holsteins. The same trend held for protein, as Jerseys improved by 20 pounds compared to 18 for Holsteins in 2020.
What does this mean for the collective U.S. dairy industry? With well over 80% of farm milk going into manufactured dairy products such as cheese, whey proteins, butter and yogurt, milk solids matter more than ever.
“These days, 100 pounds of milk from the average U.S. dairy farm yields 11.2 pounds of cheese,” Geiger explains. “Just a decade ago, that yield was closer to 10.1 pounds. The same holds true for butter, as yields from 100 pounds of milk moved from 4.4 to 5 pounds of butter. If sustainability is among the dairy industry’s collective goals, genomics is making a major difference in reaching that goal.”