Management of qualitative traits
Meat & Livestock Australia May 10, 2024
Qualitative traits, such as horn/poll status and coat colour, are traits that can be categorised into distinct groups. They are very similar to genetic conditions, except that they do not directly affect performance and are generally considered positive influences.
DNA tests are available for some qualitative traits. Results of these DNA tests can assist cattle producers to identify desirable animals for their breeding programs.
Horn/poll example
Poll is dominant over horn, this means that animals will only display horns if they have two copies of the horn allele.
Genotype
Genotype
Physical appearance
Homozygous polled (PP)
Two copies of the poll allele
Polled or may be scurred
Heterozygous polled (Ph)
One copy of the poll allele and one copy of the horn allele
Polled or may be scurred
Horned (hh)
Two copies of the horn allele
Horned
If you are aiming to breed polled calves, the safest option is to use a homozygous polled sire:
- Homozygous polled (PP) bulls can only produce polled calves, even when joined to heterozygous polled (Ph) or horned (hh) cows
- Heterozygous polled (Ph) bulls will produce some horned calves if mated to heterozygous polled (Ph) or horned (hh) cows
The gene(s) responsible for horn/poll inheritance are different to those responsible for scurs. Scurs occurs when animals have a horn-like structure that is not attached to the skull. There is no DNA test available for scurs, but research is ongoing.
Optional reading: This article contains further information on Breeding for Polledness.
Coat colour example
There are a number of genes that influence coat colour. These can be broken into two groups:
- Base Colour: Black or Red
- Other: Spotting, Dilution, Roan and Brindle are caused by other genes acting on the base coat colour
In the base colours black is dominant over red, giving three potential genotypes.
Genotype
Genotype
Physical appearance
Homozygous black
Two copies of the black allele
Black
Heterozygous black
One copy of the black allele and one copy of the red allele (red carrier)
Black
Red
Two copies of the red allele
Red
Optional reading: This article contains further information on the inheritance of coat colour.