DNA technology can help improve herd genetics

Genomic testing enhances the selection of quality cattle. Today, producers can compare cattle phenotypes with highly accurate EPDs to select the best animals for their herd.

Traditional EPD calculation uses three areas of data: estimates from the animal’s recorded ancestry; the animal’s individual performance; and data collected from relatives, including calves produced by the animal.

Under this method, a bull must produce hundreds of calves to achieve high-accuracy EPDs. It often takes several generations of data collection to document his performance. However, genomic testing can provide accurate EPD data before the bull ever produces a calf.

Testing begins with research identifying the genetic merit of animals according to their DNA. Dr. Jerry Taylor, University of Missouri professor of genomics and animal science, is a leader in cattle genomic testing. He said his research includes two phases.

The discovery phase is data collection. Researchers collect DNA samples and EPDs on several thousand animals from the same breed, often times bulls. They use glass chips to mark genetic variation at 50,000 or more points in the DNA sequence. Taylor uses a high-density genotyping test to chemically identify AA, AB and BB genotypes at each point in the DNA. Each B allele is responsible for genetic variation. Taylor numbers each genotype according to the number of B alleles then creates a statistical model to estimate the contribution of each DNA variant to an animal’s EPD.

The next phase is validation. Using the EPD prediction model he built, Taylor genotypes a second set of animals. He then compares the results with their EPDs or phenotype to benchmark his accuracy.

According to Taylor, genomic tests are available for 17 traits recorded by the American Angus Association. GeneSeek, based in Lincoln, Neb., offers testing commercially to producers. Several breed associations work with GeneSeek to provide EPD estimates to their producers. With this technology, producers can collect DNA samples on young cattle by pulling a tail hair or collecting ear tissue when tagging. GeneSeek genotypes the DNA and runs it through a genetic prediction model for each trait. “You could come back with a set of EPDs that have an accuracy of 60 to 70 percent,” Taylor said. Under traditional EPD calculation, it could take several years to achieve accuracy that high.

CHANGING THE GAME

Genomic testing has transformed the process of sire selection for AI companies. Select Sires Inc. started testing beef bulls in 2008.

“Genomic testing had an influence on our accuracy of selection, particularly in young sires that were unproven. It helped us identify bulls that were superior for traits of economic importance. Today we would not even bring a bull in [our lineup], particularly in the Angus breed, that didn’t have a genomic DNA score,” said Dr. Aaron Arnett, beef genetics vice president for Select Sires.

Arnett said the accuracy accelerates genetic improvement. It creates demand for young bulls that wouldn’t be proven for several years under the traditional progeny tests, and it gives producers the confidence to use those bulls.

“You couldn’t be in the AI industry without doing genomics technology—it’s cutting edge,” said Willie

Altenburg, Genex Cooperative Inc. beef development associate vice president. Genomic testing allows Genex to reduce the number of bulls it progeny tests, which saves time and money. “I think it has shortened the selection interval because it’s allowed us to choose bulls at a much earlier age. Then we can intensify the selection pressure,” said Altenburg.

Genex uses two phases of sire selection. The traditional phase selects bulls as yearlings based on performance tests and phenotype. Genex tests the selected bulls to determine if their genomic profile adds value to the company’s sire lineup.

A newer phase focuses on the international AI market. Certain semen export markets have stringent health qualifications. Markets in China and the European Union won’t accept animals with IBR or BVD. Animals vaccinated for those diseases show positive when tested.

To comply with these health guidelines, Genex uses genomic testing on six-week-old bull calves. If the bull’s genotype is valuable, Genex requests the producer not administer any vaccines not accepted by international markets.

DATA ADDS VALUE

Genex sales rep and Hereford seedstock producer John Ridder began testing his herd bulls in 2012. Ridder’s first genomic test was on FTF Prospector 145Y, a bull now featured in the Genex sire catalog. “He was a little high on birth weight but after he was genomically tested he was actually a calving-ease bull,” Ridder said.

Calves sired by the bull confirmed the test and convinced Ridder the technology worked. Last fall, he started testing the whole calf crop.

To get genomic profiles, Ridder sends a hair sample to the Hereford association and receives updated EPDs. The test costs $55 per animal and includes screening for genetic defects.

“I think it’s a good investment. All the information we can gather to stand behind our product is a good thing,” Ridder said.

His family operation hosts a bull and female sale every spring and genomic tests all bulls sold. Ridder said his customers are commercial cattle producers, but are still progressive. Genomic testing adds value to cattle. “With the price of cattle, people are paying attention. They are willing to spend another $75 to 100 on a bull to get accurate predictions,” Ridder said.

TESTING FOR HEIFER SELECTION

To date, genomic testing has focused on bulls, but tests also are available to measure maternal traits in females. Arnett said commercial cattle producers benefit the most from this technology. “This can be a selection tool,” Arnett said. “For just a few dollars, they can use a reduced genomic panel that’s inexpensive. They can get a good estimate of their heifer’s ability to grow and perform. They can get an indication of the heifer’s ability to transmit carcass merit for traits like marbling. As a replacement heifer selection tool, it has huge implications for the commercial industry.”

As researchers sequence more animals, the number of genomic models will increase, allowing producers to test for more traits. The value of the technology increases and testing cost decreases. “I think we’ll see some pretty dramatic changes in technology adoption once we get to that point,” Taylor said.