Cows, like many other horned animals, can possess horns, but this is not universally true for all cattle. The presence or absence of horns in cows is influenced by both natural genetic factors and human intervention.
The Biology of Horns
Horns are permanent structures that grow from the heads of certain animals, including many cattle breeds. Each horn consists of an inner core of living bone and an outer sheath made of keratin, the same protein found in human hair and fingernails. This bony core is an extension of the frontal bone of the skull and is covered by specialized skin cells at its base that continuously produce the keratin sheath.
Horns begin to develop shortly after a calf’s birth, with small horn buds forming on the head. Around two to three months of age, these horn buds attach to the skull, and the horns begin to grow more prominently. Unlike antlers, which are shed and regrown annually, horns are never shed and continue to grow throughout the animal’s life, though most growth occurs in the first six years.
Horns serve several biological functions for cattle. They can be used for defense against predators and for establishing social hierarchy within a herd. Horns also play a role in self-grooming, allowing cattle to scratch hard-to-reach areas. Some research suggests horns may also contribute to thermoregulation, helping cows dissipate heat, as they contain blood vessels and are connected to the sinus system.
Why Not All Cows Have Horns
The absence of horns in some cows can be attributed to either their genetic makeup or specific management practices. These two factors explain the diversity observed in cattle populations.
Genetic Polling
Some cattle breeds are naturally hornless, a trait known as “polled.” This characteristic is determined by specific genes, with the polled gene being dominant over the gene for horns. This means that if a calf inherits at least one copy of the polled gene, it will typically be born without horns. Many common breeds, such as Angus and Hereford, are naturally polled due to selective breeding over generations. Breeding for polled cattle is a non-invasive way to ensure a hornless herd, which can reduce labor and animal welfare concerns associated with horn removal.
Human Intervention (Dehorning/Disbudding)
Farmers and ranchers often perform procedures called disbudding or dehorning to prevent or remove horn growth. Disbudding is performed on young calves before the horn buds attach to the skull. This procedure involves destroying the horn-producing cells (corium) at the horn bud, often using a hot iron or caustic paste.
Dehorning, on the other hand, is the removal of fully formed horns from older animals where the horn is already attached to the skull. This procedure is generally more invasive and is typically done using specialized tools. The primary reasons for these practices include enhancing safety for handlers and other animals, preventing injuries from aggressive interactions, and improving ease of management in facilities and during transport.