Dominant Polled Hereford Mutation

Warren Gammon, a young Iowa Hereford breeder, in 1901 became interested in developing a breed of cattle without horns. Mr. Gammon realized if he could develop a breed of cattle with no horns (polled) that they would not have to go through the practice of dehorning. He was specifically interested in Hereford cattle. Originally all Herefords were horned. Warren happened upon a polled offspring. The only one in the whole herd. 

• The“Sire (father),” is a horned Hereford bull with dark brown body with a white face and legs.
• The “Dam (mother),” is horned Hereford cow, also with  a dark brown body and a white face.
• The “Offspring (child),” is a Hereford calf with no horns, known as "polled." This polled calf also has a dark brown body and a white face.

The genotype for Polled/Horned are:

• homozygous polled (PP)
• heterozygous polled (Pp)
• homozygous horned (pp)

Mr. Gammon realized that polled Herefords are caused by a genetic mutation. He advertises through the American Hereford Breeders association for naturally hornless animals. He acquired four bulls and 10 cows and started his own herd of polled Herefords. He started his own breed registry called the “American Polled Herefords Association.”