The information below has been supplied by dairy marketers and other industry organizations. It has not been edited, verified or endorsed by Hoard’s Dairyman.
May 12, 2025, Reynoldsburg, Ohio—Effective June 1, 2025, the American Jersey Cattle Association (AJCA) will include Percent Jersey Ancestry (PJA) on all official documents issued by the organization. This new designation provides an added layer of transparency by indicating each animal's probable Jersey breed composition based on its pedigree and ancestors.
“This is a step forward in equipping breeders and industry partners with even more valuable, detailed information,” said John Metzger, genetic consultant for the AJCA. “Percent Jersey Ancestry will provide a clearer understanding of expected breed composition of individual animals and support informed decisions in genetic selection, marketing, and herd management.”
PJA is calculated as the average of an animal’s parents’ PJA values, tracing back through the oldest ancestors in its pedigree. It offers a more streamlined and reliable method of assessing breed ancestry, especially for determining male registry eligibility, than the previously used combination of Generation Count (GC) and Breed Base Representation (BBR).
All animals in the AJCA database will be assigned a PJA value based on their documented lineage. Moving forward, PJA will serve as the primary tool for evaluating male registry status. Specifically, bulls born after March 31, 2025, must have a Generation Count of GC {6} or higher and a minimum PJA of 94% to be eligible for registry.
The new ancestry tracking system will be integrated into AJCA’s official pedigrees, progeny reports, Animal Family Tree, and other herd management tools. While PJA becomes a central feature, Generation Count and BBR will still be displayed for reference. Each measure provides distinct insights:
- Generation Count (GC): Indicates how many generations separate a Registered Jersey from a non-Jersey or foundation animal, based on the number of Registered Jersey sires in the pedigree.
- Breed Base Representation (BBR): A genomic estimate of breed composition calculated by the Council on Dairy Cattle Breeding (CDCB), using a reference population of qualifying sires. Bulls with BBR ≥94 are standardized to a value of 100.
- Percent Jersey Ancestry (PJA): Calculated by AJCA, this pedigree-based percentage reflects the expected breed composition and will serve as the most accurate and consistent tool for assessing Jersey ancestry and registry status.
For questions or further information about PJA, please contact John Metzger, AJCA Genetic and Research Consultant, at jmetzger@usjersey.com.
For more than 150 years, the American Jersey Cattle Association has maintained performance and identification records for dairy producers and delivered programs that promote genetic improvement and profitability by increasing the value and demand for Registered Jersey™ cattle and Jersey milk. Learn more at USJersey.com or follow us on Facebook.com/USJersey.
