Polled Genetics in Beef Cattle

Polled cattle are born without horns, which removes the need to dehorn. Understanding how the trait passes on helps you plan matings and avoid surprises in the calf crop.

Key points

Polled is dominant, so one copy gives a polled animal.
Homozygous polled bulls give polled calves from every mating.
DNA tests and registration records show polled status.
Scurs are a separate trait with more complex genetics.
Select polled bulls for the whole package, not polled alone.

What polled means

A polled animal does not grow horns. Horned cattle can injure herdmates and people, bruise carcasses and make handling harder, so many producers prefer polled cattle. Polled genetics let you cut or avoid dehorning, a procedure that raises welfare and labor questions.

The polled trait occurs naturally in several breeds, and some breeds have long-established polled lines. Other breeds have horned and polled versions registered separately or together, depending on the association.

Some buyers of replacement bulls and some feeders prefer polled cattle for safety and trailer space reasons, which is one more reason to ask your own market about it.

How the trait is inherited

Polled is dominant over horned. An animal needs only one copy of the polled gene to be polled. An animal with two polled copies is homozygous polled and will pass the trait to every calf. An animal with one polled copy and one horned copy is heterozygous and passes polled to about half its calves on average.

A horned animal has two copies of the horned gene. When a heterozygous polled bull is bred to horned cows, some calves will be horned. The calves look the same as polled at birth in some cases, so the gene status of the parents is the useful information.

Homozygous polled: passes polled to all calves
Heterozygous polled: some calves may be horned
Horned: two copies of the horned gene
Scurs: small loose horn tissue, a separate trait

Testing and registration

DNA tests can tell you whether a bull or cow carries one or two copies of the polled gene. Many breed associations list the results with registration. Ask the seller for the polled status in writing, and look at what your breed association records.

Scurs are a separate matter. They are small, loose horn-like growths that can appear on animals that carry the polled gene. They are inherited differently, and the genetics are not as simple. Ask your breed association or extension geneticist what is known for your breed.

Choosing a polled bull

A homozygous polled bull on horned or heterozygous cows moves your herd toward all polled calves quickly. A heterozygous bull on horned cows will give you a mixed calf crop, which may be acceptable if you are phasing in polled genetics.

Do not choose a bull on polled status alone. A polled bull with poor calving ease, structure or fertility is a poor buy. Treat polled as one trait in a balanced selection, and check EPDs and pedigree as usual.

Confirm status through a DNA test or registration
Check calving ease, growth and fertility EPDs
Look at structure and disposition
Ask about scurs in his progeny
Match to your goals and market

Welfare and the dehorning decision

If horned calves are born, dehorning decisions should be welfare-first and vet-led. Discuss the age, method and pain management with your veterinarian, and follow any rules from certification programs or buyers you sell to. Practices and programs have their own requirements, so check them.

Using polled genetics can reduce how often the question comes up. It does not replace sound handling for any cattle that still have horns.

Whatever the dehorning method, the person doing it should be trained, and the animal's comfort should be planned for ahead of time with your vet.

Planning your herd transition

Moving to polled takes several calf crops. Start by keeping notes on which females carry horned genes, then choose bulls that move the herd steadily. Heifers born polled from polled bulls are good candidates for replacements if they also meet your other standards.

Do not cull a good horned cow only because of horns, unless your market or handling system demands it. You can still breed her to a polled bull and keep polled daughters.

Keep a simple chart of every female, her horn status and the status of the bulls you use, so you can see the transition working.

Common mistakes and what to ask

Mistakes include assuming all calves from a polled bull will be polled, buying without testing and overlooking scurs.

Ask the seller: Is this bull homozygous or heterozygous polled, and how do you know? What are the EPDs? Ask your vet about dehorning options for any horned calves, and ask your buyer whether horns affect price.

When to get help: Ask your veterinarian about dehorning methods, timing and pain management for any horned calves. Your breed association and extension geneticist can explain polled testing and how your breed records it.

Sources and further reading

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

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