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Genomic Testing in Beef Herds

Genomic tests read an animal's DNA to add information to its genetic evaluation. They help most where records are thin, and they work best alongside good herd records.

What genomic testing is

A genomic test uses a small sample, often hair or tissue, to look at markers in an animal's DNA. Those markers are compared with data from animals that have known performance records. The result is a prediction of the animal's genetic merit for various traits.

Many breed associations blend test results into their EPDs. Ask your association how this works for your breed and what testing options they offer.

The idea behind these tests is simple: animals with similar markers tend to have similar genetics. The more animals in the reference group, the better the prediction. Think of the test as one more piece of information that you combine with records, soundness and your own eye.

Where it helps most

Genomic information is most valuable when an animal has little performance data of its own. Young bulls and heifers fall into that group. A test can raise the accuracy of their predictions before they have progeny.

It can also help in herds where record keeping is limited, though it does not replace records.

Heifer selection is one common use. Testing a group of heifers gives you more to go on than weaning weight and the dam's record alone. Ask whether any other uses, such as checking for known genetic conditions, are included in the same sample.

• Young bulls with no progeny data
• Replacement heifer selection
• Seedstock herds marketing breeding cattle
• Herds checking parentage and traits together

What it cannot do

A test does not tell you how an animal will look, whether it is sound or whether it will be fertile in your environment. It does not replace a breeding soundness exam, structure evaluation or temperament assessment.

Results are predictions with some uncertainty. Keep making culling decisions based on how animals perform in your herd.

Ask your association how to read a genomic-enhanced EPD, because the numbers look just like regular EPDs, but accuracy is often higher for young animals. Results should be stored and backed up, since you may want to refer to them when selling breeding stock.

Thinking about cost and value

Testing has a fee per animal, and fees and options change. Ask your association or the laboratory for current information rather than relying on old figures. A test makes the most sense where the result will change a decision, such as which heifers to keep or which bulls to buy.

Testing every animal is not always worth it. Start with a clear question you want the test to answer.

Talk to your extension office or a seedstock producer who uses testing and ask what they learned. Their experience can save you costly mistakes. Ask the lab for a clear explanation of what it will report, so you know whether the test fits your question before you pay for it.

Working with your association

Registered herds usually work through the breed association, which specifies approved labs, sample types and how results are reported. Commercial herds may have different options, including tests offered through other programs.

Ask how the results are used, who owns the data and how it connects with your herd records.

Check whether a lab accepts samples from non-registered animals, and what the turnaround is. Plan ahead for sale dates or breeding season. A call to your association before sampling can save trouble, since each program has its own rules on forms and tags.

Handling samples and records

Careful identification is critical. A sample matched to the wrong animal gives you a wrong answer that looks right. Use clear tags, label samples at the time they are taken and record everything.

Keep results with your herd records so that you can compare predictions to performance over time.

Store sample tags and receipts with your herd records so you can trace any question back to the right animal.

Common mistakes and what to ask

Treating a test as a guarantee, skipping basic selection steps and mislabeling samples are the usual errors. Another is testing without a plan for using the result.

Ask your breed association about testing options, ask your extension office whether it fits your herd and ask your vet about sample collection if you need help. Write down the decision each test is meant to inform, and check later whether it did.

• What decision will this test help me make?
• Is the lab approved by my association?
• Are samples labeled at the time they are taken?
• How will I store the results?

More in Breeding, Genetics & Reproduction

• DNA Testing for Parentage
• Genetic Defects in Beef Cattle
• Inbreeding Avoidance
• Linebreeding Basics
• Selecting for Calving Ease
• Selecting for Weaning Weight