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The Council on Dairy Cattle Breeding (CDCB) is introducing two new calf health traits in August 2026: Resistance to Diarrhea (DIA) and Resistance to Respiratory Problems (RSP). These new genetic evaluations mark a significant step forward in helping dairy producers improve calf survival, herd health, and long-term profitability—especially in a time when replacement heifers are more valuable than ever.
In this episode of the Select Sires podcast, Host Ethan Haywood speaks with Kristen Gaddis, Ph.D., CDCB Senior Research Geneticist, about how these traits were developed, what they measure and how producers can leverage them when making breeding decisions.
Built from hundreds of thousands of real on-farm health records, the new traits reflect an industry-wide data effort. With over 250,000 scours records and 768,000 respiratory records, these evaluations provide actionable insights into genetic resistance to common calf challenges.
Like existing cow health traits, these new evaluations use Predicted Transmitting Abilities (PTAs) expressed as percentage points—meaning higher values indicate greater disease resistance. While heritability is relatively low (around 2–3%), these traits still offer meaningful genetic progress over time, particularly when combined with other selection criteria. Reliability of these traits is comparable to cow health traits when they were first introduced. DIA has a 43% reliability for Holstein genomic sires and 48% for progeny tested. RSP has a 45% reliability in Holstein genomic sires and 53% for progeny tested.
Importantly, both traits show favorable correlations with key metrics like heifer livability, productive life and mastitis resistance, making them valuable tools in broader herd improvement strategies.
With limited heifer inventories and an increased focus on capturing beef-on-dairy value, each calf’s health and performance matters. These new evaluations empower producers to make smarter genetic decisions while reinforcing the importance of good management and accurate data recording.
As more farms contribute data through Dairy Herd Improvement (DHI) systems, these traits will continue to improve, making this a collaborative advancement for the dairy industry.
For more information about the August 2026 Evaluation updates please visit https://uscdcb.com/august-2026-evaluations/.