The Spring 2017 genetic evaluation is now available, including the first genomically-enhanced EPDs in the Shorthorn breed. The GE-EPDs will include Birth Weight, Weaning Weight, Yearling Weight, and Carcass Weight. Also, the new Stayability EPDs are now available.
The GE-EPDs are calculated using technology known as the blended method. Also known as the two-step method, the genetic evaluation is run the same way as it has always been calculated. Then, any animals with genomic information available have that information incorporated into the EPDs. While some change in EPD value is possible, the noticeable difference will be increased accuracies for animals with GE-EPDs. Young animals with low accuracies see the largest increase, while older, higher accuracy sires and dams will not see much (if any)change.
IGS developed the Stayability EPD as a tool to identify animals with genetic potential to produce daughters that stay in the herd longer. Stayability is abbreviated ST in the online registry, and it is part of the IGS multi-breed evaluation and can be compared to ST EPDs in other IGS partner breeds. Stayability is the probability of an animal’s daughters staying in the herd until six years of age. The ST EPD is expressed as a percentage. When comparing two bulls, if bull A has a ST EPD of +7, while bull B has a ST EPD of +2, you would expect 5 percent more daughters of bull A to stay in the herd to the age of six.
The ST EPD is calculated using a method known as the single step method and BOLT software. The new software will combine pedigree, phenotypic data, and available genomic information into the genetic evaluation simultaneously. In the future, IGS will be using BOLT to calculate all EPDs. For ST EPDs, a cow’s lifetime calving records are important to collect as we continue to build the database. If you have any questions on GE-EPDs or ST EPD, please contact Matt Woolfolk at ASA, firstname.lastname@example.org.