by Dr. Elizabeth Dressler, ASA Lead Geneticist
Replacement heifer development represents a significant financial investment in a cow-calf operation.
A heifer that fails to conceive during their first breeding season is a significant economic investment that returns substantially less value to the operation compared to a productive female. Improving fertility in replacement females is therefore one of the most effective ways to improve long-term herd profitability.
Expected progeny differences (EPD) for heifer pregnancy (HP) have been released by the American Simmental Association (ASA) in a research release format. This EPD is designed to help producers select sires whose daughters are more likely to conceive during their first breeding season as heifers.
To view the research release of HP EPD on high-use sires and high-accuracy HP EPD animals, please scan the QR code below. As a research EPD, HP will not yet be evaluated weekly or published on an animal page on Herdbook.org.
The HP EPD is expressed as the percentage of daughters that become pregnant during their first breeding season as heifers. The HP EPD predicts differences among individuals (typically sires) in the percentage of their daughters that will conceive and subsequently calve at two years of age. A greater EPD is favorable. For example:
Bull A = 10 HP EPD
Bull B = 5 HP EPD
Difference = 5%
Daughters from bull A are expected to have a 5% greater chance of becoming pregnant during their first breeding season compared to Bull B’s daughters. In other words, you can expect an average of five more pregnant daughters as heifers out of 100 from Bull A compared with Bull B, assuming daughters were managed similarly.
ASA’s Total Herd Enrollment (THE) program is pivotal to the collection and reporting of data for the HP EPD. The phenotypic dataset is based on calving and productivity information reported by breeders enrolled in THE. A heifer’s phenotype is categorized as either a success or failure of becoming pregnant over an entire 90-day breeding season.
The HP EPD was developed by International Genetics Solutions (IGS). The research release of HP reflects IGS and ASA’s commitment to the development of genetic tools for economically relevant traits.
This EPD has undergone an extensive validation process as part of its development. Membership is encouraged to review the research release predictions for HP. Members that have feedback or any questions should contact Dr. Elizabeth Dressler, ASA Geneticist, at
