New EPDs and teat and udder research report published by the American Angus Association and Angus Genetics Inc.

The American Angus Association® and Angus Genetics Inc. (AGI®) released two new research findings on expected progeny differences (rEPDs) on August 22. The rEPDs characterize teat size and udder attachment traits and are based on phenotypic data collected from association members, pedigrees and genotypes in a one-step genetic scoring model..

Good udder structure plays an important role in beef production as it contributes to the survival and growth of the calf and the longevity of the cow. rEPDs for teat size determination (TEAT) and udder attachment determination (UDDR) expand the choices available to Angus breeders to improve maternal function and productivity of their herds.

“We know that these two traits are of interest to members and are pleased to be able to release the research EPDs after a multi-year research project that would not be possible without members' data,” said Esther Tarpoff, the association's director of performance programs. “Members have quickly embraced the collection of these phenotypes, as demonstrated by the number of data sets for each trait used to create the research EPDs.”

New research EPDs complement selection tools for Angus producers who prioritize maternal traits.

More than 148,000 phenotypic records for each trait have been collected from 87,000 cows to supplement the dataset for the rEPDs, with more being added each calving season. Records are collected by members within 24 hours of a calving event. Females are given an individual score for both teat size and udder attachment on a scale of 1 to 9. Detailed scoring guides can be found at angus.org.

“Over the past few years, we have focused on validating the importance of the Angus breed as the matriarch of the U.S. beef industry, as it has historically been called,” said Kelli Retallick-Riley, president of AGI. “From AGI's perspective, this means objectively characterizing maternal traits of economic importance so that users of Angus genetics have the selection tools needed to make genetic changes.”

Submitted scores range from 1 to 9 and represent the full rating scale. Analysis of the nearly 300,000 records showed overall good udder structure in the Angus cows reported. The average score was 6.6 for both traits, indicating medium to small teats and medium to tight udders. For more TEAT and UDDR research results, see angus.org in the full report.

“We know that the pace of genetic change is faster than ever before, with many breeding operations changing bulls frequently,” said Retallick-Riley. “In some cases, young bulls are replaced before most of their daughters have reached their second year of production. Because of this, maternal traits such as udder shape are becoming even more important to ensure we make informed breeding decisions.”

The release of TEAT and UDDR follows that of the Functional Longevity (FL) rEPD, which measures a cow's ability to produce a calf year after year. The three rEPDs are currently available to members who were involved in the early phenotypic data collection for the respective traits, which enabled rEPDs to come to fruition. A list of AI sires for each of the rEPDs is available to members on the relevant research pages at angus.org.

The three rEPDS are expected to be released as weekly production EPDs as part of the annual evaluation updates in late spring 2025. Research is currently underway on how to integrate these three new traits into the Maternal Weaned Calf Value Index ($M), and potential updates to the index will likely be made as part of the spring update.