Every five years, the Council on Dairy Cattle Breeding (CDCB) updates the genetic base to reflect the ongoing progress in dairy genetics. This ensures predicted transmitting abilities (PTAs) remain relevant by comparing today’s animals to a more current reference population. Today, PTAs are based on cows born in 2015; but, after the April 2025 update, they will be measured against cows born in 2020. While the genetics of individual animals remain unchanged, their PTA values will shift to reflect this new baseline. Table A shows the expected base change to occur in 2025 compared to the previous two base changes the Holstein breed has experienced.
As the genetic base change will be applied evenly across all animals in the industry, it’s important to remember additional data will continue to be incorporated. As a result, we will see some variations to the changes of individual animals. Ultimately, it’s a multifactorial base change, so it’s important to reference relative rank when comparing animals.
Relying on relative rank in your herd to categorize the female population or the sires you are choosing, is the best way to remain confident you’re selecting the right genetics to create replacements for your herd. For example, if Herd Health Profit Dollars® (HHP$®) is your selection index, you can use the rank of females on HHP$ in your herd to guide mating and breeding decisions. Similarly, on the sire side, utilizing the HHP$ relative rank among sires will help navigate the base change and help selection on sires compared to others.
Navigating the combined changes in genetic base and Net Merit
Along with the April base change, CDCB will adjust the Net Merit (NM$) formula. The main adjustments include an increase in emphasis on fluid milk (M); decrease to overall combined fat and protein (CFP); decrease on productive life (PL); decrease on mastitis (SCS); decrease on fertility; and increase on smaller stature cattle with more focus on dairy form. The decrease in emphasis of CFP is driven by lowering the weight on protein and increasing the importance of butterfat. Table B shows the percent change to the April 2025 NM$ formula compared to the current formula.
Combining both the genetic-base change and the NM$ formula adjustment at the same time will create complexity in evaluating the impact of each on an animal’s genetic profile. With any change, it’s a great time to evaluate the metrics important to your herd and what makes your operation profitable.
Focusing on long-lasting, profitable cows
Cows being profitable for longer is a critical part of our industry. Continual focus on CFP, fertility, mastitis resistance, and moderation to size all lead to profitable success. HHP$ is staying true to these values and focusing on making cows that last longer and are more profitable. As replacement numbers continue to be at an all-time low, it’s a great time to continue focusing on breeding long-lasting profitable cows. HHP$ is an excellent selection index for this. Table C shows the average of the top 100 Active Holstein Proven and Genomic sires ranked by various indexes.
Author: Wes Vomastic, CentralStar Director of A.I. • [email protected]