Two significant updates will be implemented in the April 1, 2025, genetic evaluations published by CDCB – a revision to the lifetime merit indices and a genetic base change. The CDCB Board of Directors approved these revisions at their December 18, 2024, meeting.

The lifetime merit indices –Net Merit $, Cheese Merit $, Fluid Merit $, and Grazing Merit $ – are updated periodically to reflect new traits, new research and current market data. The April 2025 revision adjusts the weights placed on individual traits and composite indices due to changes in the economic values of traits. Most notable is the enhanced commitment to dairy cattle genetic improvement and profitability through feed efficiency, component-based milk pricing, and fertility. Calculations show a 0.992 correlation between the April 2025 and current formulas, indicating little reranking expected for most animals.

Click here for more detail and a table of the expected relative value of traits in the revised April 2025 Net Merit $ formula, compared to weights in the current formula.

Genetic Base Change in April
These merit index values, along with the 49 individual selection traits and composites produced by CDCB, will be expressed on an updated genetic base relative to dairy cows born in 2020. In the U.S., this update occurs every five years to best align selection tools with the current dairy herd.

Final base change values will be shared with the April 2025 evaluation release. Preliminary estimations of the changes in Predicted Transmitting Ability (PTA) values are outlined here. Note that the estimated change in Holstein Final Score has been updated, compared to the article initially sent by CDCB as the Final Score number was inverted in the December 20 correspondence.

CDCB will share additional information – including a forthcoming technical document from USDA-AGIL on the merit index – at uscdcb.com, through this e-newsletter, CDCB LinkedIn and other channels.