Polledness is a genetic mutation that causes animals within a horned cattle breed to not develop horns.  In the South Devon breed there are naturally occurring polled genetic lines which are now quite widespread thanks to individual herd breeding programmes specifically used to increase the percentage of polled cattle.

Polling is a trait that many breeders are looking to select for, for reasons including: injury to other cattle from horns; larger space requirements for transporting horned cattle; stress caused at de-horning which may reduce performance; and risk to staff during handling of horned cattle.

The selection for the polled trait is complicated however by the inability to visually distinguish between a polled animal carrying two copies of the gene (homozygous polled = PP), and an individual with only one copy (heterozygous polled = HP).

A homozygous polled animal (PP) will not produce horned offspring, but calves may have scurs.  A heterozygous polled animal (HP) will produce on average 50% of horned calves and 50% polled.

If a member wishes to register a bull as polled, the status must be verified by DNA testing.  In addition, any female that is entered in a show’s polled class must also be DNA tested for polling.

The Society advises that, in order to have a successful polling programme in a herd, polled animals need to be of an acceptable quality for all other traits of interest before consideration is given to polling.

With thanks to Lucy Webb-Wilson, Signet, for this information