Improving EPD Accuracy With DNA Tests
JOPLIN, Mo. (Aug. 31, 2011) — The advent of molecular information in the form of DNA tests for genetic traits has created considerable excitement within the beef industry. According to University of California-Davis geneticist Alison Van Eenennaam, it has also created some confusion. In a presentation to the Applied Reproductive Strategies for Beef Cattle (ARSBC) conference in Joplin, Mo., Van Eenennaam said there is uncertainty among beef producers about how DNA information should be used in making genetic selection decisions.While various gene markers associated with certain traits have been identified, Van Eenennaam reminded her audience that available DNA tests explain only a portion of the overall genetic variation for a trait of interest. A specific trait, such as marbling, may be influenced by thousands of genes for which there are not yet any available tests.
Alison Van Eenennaam reminded the audience that available DNA tests explain only a portion of the overall genetic variation for a trait of interest.
Van Eenennaam warned agains using DNA marker test results in place of expected progeny difference (EPD) and economic index values for making selection decisions. The power of this technology, she said, will only be fully exploited when it is integrated into national cattle evaluations that result in calculations of EPDs.
“The ideal situation,” stated Van Eenennaam, “is to use this molecular information to improve the accuracy of EPDs.”
That has begun, she added, noting how the American Angus Association is adding molecular information to the traditional phenotypic information (pedigree, individual performance and progeny performance data) used to calculate EPDs. The inclusion of DNA information should provide the greatest benefit to young animals with little progeny data. Van Eenennaam said the improvement to accuracy resulting from including DNA information would be similar to adding performance data from 7 to 20 progeny.
As DNA testing becomes more comprehensive and encompasses a larger number of traits, it should provide a selection tool for traits where no other information or selection criteria exist. This could include economically relevant traits, including cow and feedlot efficiency, and disease resistance.
Regarding the economic value of DNA testing, Van Eenennaam said it is likely to be of greater value to producers of elite seedstock.
“The value depends on your place in the chain and your opportunity for value capture,” explained Van Eenennaam. “For most producers, the cost has to come down to make it pencil, especially in commercial operations.”
Van Eenennam spoke during Wednesday's ARSBC session focused on the genomic and economic considerations of producing high-quality cattle. For more information, visit the Newsroom at www.appliedreprostrategies.com to view the PowerPoint slides and proceedings paper submitted by Van Eenennaam to accompany her presentation. Audio of the presentation will be available soon.
Comprehensive coverage of the symposium is available online at www.appliedreprostrategies.com. Compiled by Angus Productions Inc. (API), the site is made possible through sponsorship by the Beef Reproductive Task Force, SEK Genetics, and liveauctions.tv. Coverage includes summaries of the speaker presentations, PowerPoints, proceedings and audio.
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