From the time when livestock was first domesticated, modifications to the wild types have been selected both for animal husbandry and aesthetic reasons. Unique and large horns define cattle breeds such as Texas Longhorn, Highland Cattle and Ankole Watusi. However, in modern times many cattle are maintained in more crowded conditions such as barns and small fenced pastures where polled phenotypes are more desirable for both beef and dairy breeds.
Recently, candidate mutations associated with polled phenotype in European breeds of cattle were found. There are 2 independent origins of polled, one found in Holstein-Friesian and Jersey breeds (Pf), the other in many European breeds of Celtic origin (Pc) such as Angus, Blonde d’Aquitaine, Dexter, Limousin, Charolais, and Hereford, among others. Polledness is dominant; a polled animal can have one or two copies of the gene. All offspring of a bull with 2 copies of polled (homozygous) will be polled. Genetic testing is a cost-effective means to determine if a polled animal has 1 or 2 copies of the gene.
The Veterinary Genetics Laboratory offers a test for the polled gene to assist breeders in selecting cattle that have 2 copies of Polled gene.
Results reported as:
|H/H||HORNED. No copies of either Polled molecular marker are present.|
|Pf/H||POLLED. One copy of the Polled-Friesian molecular marker is present. At least 50% of the offspring will be polled.|
|Pf/Pf||POLLED. Two copies of the Polled-Friesian molecular marker are present. All offspring will be polled.|
|Pc/H||POLLED. One copy of the Polled-Celtic molecular marker is present. At least 50% of the offspring will be polled.|
|Pc/Pc||POLLED. Two copies of the Polled-Celtic molecular marker are present. All offspring will be polled.|
|Pc/Pf||POLLED. One copy of Polled-Celtic and 1 copy of Polled-Friesian molecular markers are present. All offspring will be polled.|
Medugorac I, D Seichter, A Graf et al. Bovine Polledness – An autosomal dominant trait with allelic heterogeneity. PLoS One 7(6): e39477, 2012.