Not all cattle have horns, as their development is influenced by genetics and human intervention. Horns are a natural characteristic for many bovine breeds, varying in size and shape. Understanding the biological basis of horns and the reasons for their absence provides a comprehensive view of this bovine trait.
The Horned Truth
Cattle horns are permanent structures composed of a bony core covered by a layer of keratin. Keratin is the same fibrous protein found in human fingernails and hair. This bony core extends from the frontal bone of the skull. Horn development begins early, with calves born with small horn buds on their heads. These buds are initially distinct from the skull, but around eight weeks of age, they attach to the skull and continue to grow.
Horns grow continuously throughout a cow’s life. While growth slows as the animal ages, it never ceases. The size and shape of horns can vary significantly based on the cattle breed and the animal’s sex. For instance, breeds like the Texas Longhorn are known for their exceptionally large horns.
Why Some Cows Lack Horns
The absence of horns in some cattle is primarily due to two factors: genetic polling and dehorning practices. Genetic polling refers to the natural hornless trait found in certain cattle breeds. This occurs due to a dominant gene, meaning that cattle carrying this gene are born without horns and will not develop them. Examples of naturally polled breeds include Angus and Galloway, which have been selectively bred for this characteristic over generations.
Dehorning is a common practice where horns are intentionally removed or prevented from growing. This procedure is performed for various reasons, including safety for both handlers and other animals, as horns can cause injuries. Horned animals also require more space during transport and at feed bunks, and they can damage farm infrastructure.
Disbudding, a less invasive form of dehorning, involves destroying the horn-producing cells in very young calves before the horn buds attach to the skull, typically within the first few weeks of life. Methods for disbudding include using a hot iron or caustic paste to prevent horn growth. Dehorning mature horns in older animals is a more involved procedure, often requiring veterinary intervention due to the horn’s attachment to the skull and the presence of blood vessels and nerves.
The Purpose of Horns
For cattle that possess them, horns serve several natural functions. They can be used for defense against predators, protecting themselves and their offspring. Horns also play a role in establishing and maintaining social hierarchy within a herd, as cattle use them in displays of strength to determine dominance.
Beyond defense and social interactions, horns can assist cattle in other behaviors, such as scratching hard-to-reach areas. Some research also suggests a role for horns in thermoregulation, helping cattle dissipate heat in warmer climates. Horns may also contribute to a cow’s overall well-being and metabolism.
Horns Versus Antlers
A common point of confusion is the distinction between horns and antlers, as they are often mistakenly used interchangeably. Horns are permanent structures that are never shed. They consist of a bony core that is an extension of the skull, covered by a keratin sheath. Horns grow continuously throughout an animal’s life and are unbranched. Both male and female bovids can possess horns, though male horns are often larger.
Antlers, in contrast, are bony structures that are shed and regrown annually. They are made entirely of bone and are branched. Antlers are primarily found on male members of the deer family (Cervidae), with the exception of caribou where females also grow them. During their growth phase, antlers are covered in a soft, vascular skin called “velvet,” which is later shed.