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Range Beef Cow Symposium: Markers and EPDs work ‘hand in hand’

Progressive Cattleman Editor David Cooper Published on 16 December 2011
Dr. Jack Whittier of Colorado State University

The beef industry is evolving with more accurate levels of genomic testing, allowing producers to select superior animals and maximize efficiency, said Jack Whittier, beef specialist for Colorado State University at the Range Beef Cow Symposium on Nov. 30.

Providing a history of bovine genomics over the past decade, Whittier told participants at the conference held in Mitchell, Nebraska that EPDs (expected progeny differences) have been the main driver over the past 25 years in genomic data “and they will continue to be so.”

But the process for establishing an EPD is very slow and meticulous, Whittier said, and involves proving progeny with lengthy testing. Testing for a bull will typically reach up to $25,000 in the EPD evaluation process, Whittier said, adding that “Only one in eight of the bulls that get through that graduation program of progeny testing ultimately become an active bull.”

Those obstacles have led to the emerging field of DNA marker tests that provide more accuracy and expediency to genomic testing.

Whittier explained how DNA in an animal’s genetic code will vary based on the sequence of various protein pairs. “These base pairs become an important component and are the key to the genomic predictability and understanding of processes today,” he said.

Single Nucleotide Polymorphisms, or SNPs, serve as the genetic markers in DNA that predict cattle performance. “That’s a flag along the chain of information that has been referenced to specific genes in how the animal behaves, grows and reproduces,” Whittier said.

SNPs differ from one animal to another. These genetic markers allow the allow cattle’s genomic inheritance to be identified.

Chemists and electronic engineers have developed SNP chips that use beads that recognize specific sequences of DNA. When a sample of blood, semen or hair is applied to a SNP chip, the beads will lighten in the test to indicate DNA sequences – and identify their genotypic pattern.

Whittier said the industry started with 5K chips, then 50K chips and grew as large as 750K. He likened the technology to cell phone coverage, with more markers in a test that can find genes in a pattern.

Genetic defects related to curly calf syndrome were identified through the help of marker testing, with additional breed testing to emerge in following years. Now testing through Merial and Pfizer, the two companies with the genetic test technology, costs around $38 for a profile.

Compared with EPD testing, genetic marker tests provide a faster result for traits in screening tests, and they can also be done at an earlier age, Whittier said. He also said producers will see EPDs grow more accurate as they are coupled with molecular DNA information.

The reliance upon statistical testing has changed the way producers select bulls, Whittier said. Where selections used to be made based on looks, origin and reputation, today the genetic pedigree is based on analyzed performance in the progeny.

Whittier compared the technology to the “Moneyball” principle applied in professional baseball, where scouts began building winning teams using players’ performance statistics in run production and on-base percentage rather than subjective criteria assessing overall talent. Cattle producers, Whittier said, can likewise use statistical genetic data to improve and increase their herds.

Although the tools can accelerate genetic progress with faster decisions, “Markers are not a replacement for EPDs; they go hand in hand,” Whittier summarized. “Good genetics will never overcome a poor environment, or poor management. They’re not a silver bullet.” end_mark

Dr. Jack Whittier of Colorado State University said today's growing genomic technology is meant to work with proven testing methods that create EPDs.