Opportunities for Selection: Level 2
The DNA panels now becoming commercially available and those on the horizon are set to usher in the genomic-enabled era.
by Troy Smith for Angus Productions Inc.
CASPER, Wyo. (Dec. 1, 2009) — When trying to make change through genetic selection, it boils down to three things — accuracy of the breeding value information, intensity of selection and interval between generations, says Ronnie Green, global director of technical services for Pfizer Animal Genetics.
Green discussed advances in DNA testing technology, its increasing use in genetic selection, and other applications for managing cattle production at the 2009 Range Beef Cow Symposium in Casper, Wyo., Dec. 1-3. Approximately 700 cattlemen were in attendance.
“Discovery of the full genome sequence has driven innovation at unexpected speed,” said Ronnie Green of Pfizer Animal Genetics. “We’ve moved from a few markers for a few traits to more markers for more traits, and we’re moving toward identification of thousands and thousands more.”Describing what he called the “evaluation evolution,” Green said selection tools began with visual appraisal, followed by the addition of pedigree information. Collection and evaluation of individual and progeny performance data led to the calculation of expected progeny difference (EPD) values for various economically important traits. Then came methods for considering multiple EPDs simultaneously through the use of selection indices.
The challenge, Green said, is calculating accurate EPDs for young animals lacking progeny data. Interim EPDs based on parental data often change dramatically as actual data becomes available. Another challenge is the lack of EPDs for certain important traits that are difficult or very expensive to measure.
“Now we’re moving into an era of selection tools based on DNA markers and panels,” stated Green, noting how researchers continue to identify more beef genome locations associated with specific traits. “Discovery of the full genome sequence has driven innovation at unexpected speed. We’ve moved from a few markers for a few traits to more markers for more traits, and we’re moving toward identification of thousands and thousands more.”
Green described Pfizer’s GeneSTAR® “Molecular Value Predictions” (MVPs) based on the phenotypic effects of specific markers associated with traits of interest. While early DNA testing was based on individual markers affecting a single trait, a marker panel consists of markers affecting multiple traits simultaneously. Just as the addition of more progeny data increases the accuracy of EPDs, Green explained, the addition of more markers increases the reliability of MVPs.
To date, DNA testing for selection has been most applicable to seedstock producers, but Green predicted the coming of practical and affordable application by commercial segments of beef production.
“In my opinion, the biggest value is beyond the seedstock industry, as the technology is used in predicting an animal’s phenotypic performance,” Green stated, noting feedlot application for sorting cattle into groups that can be managed to optimum end points based on predicted feed efficiency and other performance traits.
“This next decade, I believe, will be the genome-enabled era, when you will see how to get real value from the technology,” Green concluded.
Editor’s Note: API's coverage of the event is made available for distribution to all media via an agreement with the Range Beef Cow Symposium Committee and API. Headquartered in Saint Joseph, Mo., API publishes the Angus Journal, the Angus Beef Bulletin, the Angus Beef Bulletin EXTRA, and the Angus e-List, as well as providing online coverage of events and topics pertinent to cattlemen through the API Virtual Library. For questions about this site, or to notifiy us of broken links, click here.