Cattle are a diverse group, and while many associate them with horns, not all cows possess these features. The presence or absence of horns in female cattle depends on their genetic makeup and human management practices. Understanding these factors helps clarify why some cows have horns and others do not.
The Biology of Horn Growth
Horns are permanent structures found on the heads of some cattle, consisting of a bony core covered by a layer of keratin, the same protein found in human fingernails and hair. These horns begin to develop early in a calf’s life as small horn buds, which are initially unattached to the skull. As the calf grows, around two to three months of age, these horn buds fuse with the frontal bone of the skull.
Once attached, the horns continue to grow throughout the animal’s life, though the most significant growth occurs within the first few years. The hollow interior of a mature horn contains an extension of the animal’s frontal sinus, along with blood vessels and nerves. This means that horns are living tissue, which is why their removal requires careful consideration.
Breeds Where Female Cows Have Horns
Many cattle breeds naturally develop horns in both males and females, with female horns often exhibiting distinct characteristics compared to those of bulls. The Texas Longhorn is known for its impressive horns that can span over seven feet. Female Texas Longhorns typically have horns that are longer and more twisted than those of bulls, which tend to be shorter and thicker.
Another breed where female cows commonly have horns is the Highland cattle, originating from Scotland. Their horns are long, wide, and curve outward and upward. In female Highlands, the horns are narrower at the base and finer at the tip compared to bulls, often exhibiting an upward curve.
Ayrshire cattle, a dairy breed, traditionally had horns often reaching a foot or more in length, curving outwards, upwards, and slightly backward. While once a hallmark of the breed, these horns are less common in modern Ayrshires due to management practices. Other horned breeds include the Ankole-Watusi, famous for its exceptionally large horn span, and some varieties of Hereford cattle.
Why Some Cows Lack Horns
Some cows lack horns due to a natural genetic trait or intentional human intervention. The genetic condition known as “polled” causes cattle to be born without horns. This trait is determined by a dominant gene, meaning that an animal needs only one copy of the polled gene to be hornless. If a calf inherits the polled gene from even one parent, it will likely be polled.
Many cattle that would naturally grow horns undergo dehorning or disbudding. Disbudding involves destroying the horn-producing cells in very young calves, often before the horn buds attach to the skull. This process is performed when calves are only a few weeks old, using methods like caustic paste or a hot iron.
Dehorning, performed on older calves where horns have already attached to the skull, involves physically removing the developed horns and associated tissue. These practices are undertaken primarily for safety, reducing the risk of injury to other cattle, handlers, and the animals themselves in crowded environments or during transport.