Genetic progress leads to formula changes

WAUPUN, Wis. — Driven by data, the dairy industry requires producers to constantly reevaluate information to make the best decisions for continued improvement.

Three times a year, new genetic information is provided by the Council on Dairy Cattle Breeding in the form of proofs. The most recent round of proofs came out April 1, with changes of note being made to the formulas for both Net Merit and Cheese Merit, as well as the 5-year base change.

Kevin Jorgensen, senior Holstein sire analyst for Select Sires Inc., said the 5-year base change is the measure of genetic progress made within each breed over five years. To readjust genetic levels, Jorgensen said the 2020 cow population becomes the base of zero.

Changes will be applied to production and type, as well as health and fitness traits.

Jorgensen compared one of the more dramatic adjustments in the Holstein breed — 74 pounds of combined fat and protein — to the adjustment made two base changes ago in December 2014 of 29 pounds.

“It’s really telling how much genetic progress we’ve made, particularly in the production traits,” Jorgensen said. “We’ve made revolutionary changes, especially in (combined fat and protein). When you speak to producers, this astronomical increase in CFP is pretty direct, most people see it in their bulk tank and components on their farm. It’s not entirely genetic — there have been amazing breakthroughs in how we’re feeding cows — but genetic selection has really intensified in the last generation or generation and a half.”

The base changes are applied equally to all bulls in the population, Jorgensen said, using the example of a bull previously at 174 pounds CFP would now be at 100 pounds. Despite the change in index, the bull will remain in the same percentile. Jorgensen said like every new proof run, additional daughter data will ultimately factor into the bull’s final ranking.

Jorgensen said changes to the Net Merit and Cheese Merit formulas are based on changes in economic values since the last formula revision. Fat will be factored into the index at 31.8%, with protein applied at 13% and milk at 3.2%. Health and fitness traits will continue to comprise 21.2% of the formulation, while calving and fertility will account for 8.7%.

“Net Merit is geared for producers that want a commercially-friendly cow,” Jorgensen said. “There is more emphasis on pounds of fat, relative to protein; more emphasis on reduced body size and on the Feed Saved traits; less on productive life, but more on livability, which makes sense because cull cows are worth more at this stage of the game. There’s probably a little less emphasis on daughter fertility — they reduced a little bit on (Daughter Pregnancy Rate) and increased cow and heifer conception rates, but not to the degree that DPR was moved down.”

Cheese Merit is calculated similarly, but with a nod to cheese yield; milk is factored in at -2%, focusing on fat and protein, which comprise 48% of the formulation, Jorgensen said.

Jorgensen said the base changes and formula changes are needed to keep pace with the advancing world of dairy cattle genetics, and the speed of those advancements are the reason for some of the dramatic adjustments made.

“The reason we have a base change every five years is that used to be the span of a generation,” Jorgensen said. “With our accelerated genetic progress, our generation interval in this genomic selection era is about 21 months now. We’re accounting for 2.5 generations in that same period of time. It’s a credit to the genetic progress we’re making.”

Jorgensen said he speculates that the increased percentage in semen sales from genomic bulls over proven bulls has factored into the rapid increases and shrinking generation intervals.

Jorgensen said the volume of young bulls genomically tested is the cornerstone of that progress.

“Our selection pressure is so intense because of the critical mass of testing so many calves,” Jorgensen said. “That selection pressure is so deep that it is very rare anymore that a bull that is a huge minus on fat test would make it to a marketing lineup — he’d have to be so extreme in the other 70-some traits.”

Jorgensen said Select Sires tested 7,684 Holstein bulls in 2024, out of about 25,509 tested industry–wide. From that pool, Jorgensen said 275 bulls — just over 3% — entered the Select Sires lineup.

Jorgensen said he encourages producers to look inside their operation when weighing the various indexes in their own breeding programs.

“It’s really important for a producer to know exactly what they want,” Jorgensen said. “With the reduced number of replacement heifers we have, every heifer counts, because you don’t have another to take the place of ones you don’t like. We’re at historical lows of female replacements. Our cows are going to have to live longer.”

Jorgensen does not see that trajectory changing.

“No one is going to stop making those little black calves,” Jorgensen said. “They are way too lucrative; they can’t take that revenue stream out of their operation. It’s a huge paradigm shift in our industry. Some people might be rethinking what the right amount of heifers is and making slight adjustments there. We’re seeing a slight increase in sexed semen sales because of that. They are trying to make enough heifers with the fewest uteruses possible, so they can devote more to making those black calves.”

With rapid advancements and constant changes, Jorgensen said he advises producers to use the tools and data provided in the proofs and indexes.

“If we believe in genetics, we believe in the next generation,” Jorgensen said. “It’s not always perfect, but I believe with the genetic progress we are making, this system is far more accurate than the measures we were using in the pre-genomic era.”