DNA Testing for Parentage

When several bulls run with the cows, or when records are uncertain, a parentage test can tell you who the sire actually is. Good sampling and labeling decide whether the answer can be trusted.

Key points

Parentage testing identifies or excludes candidate parents.
It is most useful in multi-sire groups and for registration.
Follow sample instructions exactly.
Label samples at collection and double check.
Include every possible sire in the candidate list.

What parentage testing does

A parentage test compares DNA from a calf with DNA from candidate sires and dams. If the markers match, the animal is assigned to a parent. If not, that candidate is excluded.

Many breed associations require or accept parentage verification for registration, particularly in multi-sire situations or for animals produced by artificial insemination and embryo transfer. Ask your association what it requires.

Every calf has a sire and a dam, but in a pasture with several bulls, records of who bred whom can only be guessed. That guess can be wrong, and a wrong guess affects every record that follows. A sample that is clean, dry and well labeled is far less likely to be rejected or confused.

When it is useful

In a multi-sire pasture, you cannot know which bull sired a calf without testing. Parentage testing makes it possible to evaluate individual bulls and to register calves correctly.

It also helps when calving records are lost, when a calf might have been swapped at birth or when you need to confirm AI sires.

Even in single-sire groups, a bull might jump a fence or a calf might be mothered by a different cow. Testing resolves doubts that could cost you a registration or a sale. Keep the paperwork for every sample you send, since you may need to prove later which animals were tested.

Multi-sire breeding groups
Registering calves from uncertain matings
Confirming AI or embryo transfer records
Checking suspected mix-ups at calving

Collecting samples

The breed association or lab will tell you what sample type to use, such as hair with follicles or a tissue sample. Follow their instructions closely, since a poor sample may need to be repeated.

Collect samples carefully and wear clean gloves. Handle animals quietly and use proper restraint for safety. Follow manufacturer and extension guidance for chutes and headgates.

Before you collect, read the lab instructions about hair, follicles and storage. A hair sample cut with scissors rather than pulled by the root is a common reason for a failed test. Wear gloves and avoid touching the root end of hair samples, because contamination from another animal can spoil the result.

Labeling and identification

The biggest source of error is a mislabeled sample. Label at the time of collection, and match the sample to the animal's tag and registration information. Record the details at the same time.

Have a second person check the labels when possible. A wrong label cannot be corrected later.

Write a simple log: animal tag, registration number, date, sample type and the name of the person who collected it. Keep a copy with the sample.

Reading and using results

Results usually list which candidate sires are consistent with the calf and which are excluded. Keep the report with your records. If results do not match what you expected, double check the labeling and the candidate list before drawing conclusions.

Use the results to update your records, make culling decisions and choose which sires to keep.

If a calf does not match any candidate sire, consider whether an unlisted bull, a neighbor's bull or a record error could explain it. Call the lab or association for advice. If you are not sure how to read a report, call the association or lab. They can walk you through it and explain what each line means.

Costs and logistics

Fees, turnaround times and sample requirements change, so check with your association or lab before sampling. Plan ahead for registration deadlines, since delays can be costly.

Ask the lab how long results are held and how to get copies later. Keep the report with the herd records. Plan the testing well before sale dates, registration deadlines and breeding season, because delays are hard to fix later.

Common mistakes and what to ask

Mislabeling samples, collecting from the wrong animals and leaving out a possible sire from the candidate list are the usual errors. Another is waiting until the paperwork is due.

Ask your association about requirements, ask your vet or an experienced producer to show you how to collect samples and ask the lab about timelines. Keep the final report with the calf's papers so the answer is there when someone asks in a few years.

Is every possible sire sampled?
Is every sample labeled at collection?
Do I know the association's deadlines?
Have I filed results with my records?

When to get help: Ask your breed association about parentage requirements and approved labs. Your veterinarian or an experienced producer can help with correct sample collection.

Sources and further reading

Organization homepages are linked so you can search them for current guidance on this topic.

More in Breeding, Genetics & Reproduction

← Genomic Testing in Beef Herds Genetic Defects in Beef Cattle →