Many animals, particularly livestock, are recognized by the presence or absence of horns. Those born without horns, or that have had them removed, are often referred to as “polled.” This characteristic is a significant trait in animal husbandry, with various implications for animal management.
Understanding Hornless Animals
The term “polled” describes an animal that is naturally hornless. Horns are permanent structures made of a bony core covered by a layer of keratin, similar to a fingernail, which grow from the skull. This distinguishes them from antlers, which are typically found on deer and are shed and regrown annually. Many livestock breeds, such as Aberdeen Angus and some Hereford cattle, along with certain goat and sheep breeds, are naturally polled.
The Paths to Hornlessness
Animals become hornless through two primary avenues: natural genetic inheritance or human intervention. Natural genetic polling results from specific genes. In cattle, the polled gene (P) is dominant over the horned gene (h). This means an animal needs only one copy of the polled gene to be hornless. For example, a homozygous polled bull (PP) will produce polled offspring, even with a horned mother.
Human intervention, commonly known as dehorning or disbudding, involves removing or preventing horn growth in horned animals. Disbudding is performed on very young calves, usually under three weeks of age, before the horn bud attaches to the skull, using methods like a hot iron or caustic paste. For older calves, dehorning spoons or tubes can remove growing horn buds. Surgical removal, using tools like a Gigli saw, is used for larger horns in older animals, often requiring veterinary supervision.
Significance of Being Hornless
Hornlessness offers several practical benefits for domesticated animals. It enhances safety by reducing injury risks to other animals in a herd, especially in confined spaces or during transport, and to human handlers. Hornless animals are also easier to manage, requiring less space and avoiding entanglement in fences or feeders. Economically, polled cattle reduce dehorning labor costs and minimize carcass bruising. The absence of horns also promotes animal welfare by eliminating the pain and stress of dehorning, which can lead to better calf growth and overall operational efficiency.