Horned cattle represent the natural state for many breeds within the species. The prevalence of hornless, or polled, cattle in modern commercial agriculture often leads to the misunderstanding that horns are an abnormality. These permanent structures are a normal biological feature found on both males and females. While breeds like the Texas Longhorn display prominent horns, many commercial cattle, such as the Aberdeen Angus, have been selectively bred to be naturally hornless. Understanding this difference requires exploring the biology and genetics that determine the horn’s presence.
The Biological Structure of Horns
A true horn is a permanent, living structure that grows directly from the animal’s skull. It is composed of two primary parts: a bony core and a tough outer covering. The bony core is a direct extension of the frontal bone of the skull and contains blood vessels and nerves.
This living bone is enveloped by a thick sheath made of keratin, the same fibrous protein found in human hair and fingernails. The keratin sheath grows continuously from the base throughout the animal’s life, which allows the structure to withstand constant wear. This continuous growth distinguishes horns from antlers, which are shed and regrown annually.
The anatomy of the horn is complex because the bony core connects to the animal’s frontal sinus. As the cattle mature, the internal cavity of the horn core becomes an extension of this sinus cavity. This connection means that removing a fully developed horn in an older animal is a surgical procedure that risks opening the sinus, potentially leading to complications.
Genetic Factors Determining Horn Presence
The presence or absence of horns in cattle is determined by a single trait governed by Mendelian genetics. This trait is controlled by the dominant polled gene (P) over the recessive horned gene (p). An animal only needs one copy of the polled gene to be hornless.
A calf born with two recessive alleles (pp) will develop horns, as seen in breeds such as Highland cattle. Conversely, an animal with two dominant alleles (PP) or one dominant and one recessive allele (Pp) will be naturally polled. Breeders use DNA testing to confirm if a bull is homozygous polled (PP), guaranteeing all its offspring will be polled even when bred with horned cows.
Breeding for the polled trait is standard practice in commercial herds to avoid physical horn removal. Naturally polled breeds like Angus and Red Poll are favored in beef production. In some cases, an irregular growth called a “scur” may appear, which is a partial or deformed horn not fully attached to the skull.
Practical Management of Horned Cattle
In modern farming systems, the removal of horns, either through disbudding or dehorning, is a common practice driven primarily by safety and economic concerns. Horned cattle pose a greater risk of injury to farm handlers, veterinarians, and other livestock. These injuries often result in bruising and carcass damage, leading to financial losses at processing.
The management technique depends on the age of the animal. Disbudding is the preferred method, involving the destruction or removal of the small horn bud in calves, ideally before they are two months old. At this early stage, the horn bud is not attached to the skull bone, which minimizes pain and avoids opening the frontal sinus. Caustic paste or a hot iron are common tools used for disbudding.
Dehorning, which is the removal of a fully developed horn on an older animal, is a more invasive surgical procedure. It involves removing the horn and a ring of skin around the base, which is more painful and carries a higher risk of infection because of the connection to the sinus.
Veterinary best practice mandates the use of pain management, including local anesthesia and non-steroidal anti-inflammatory drugs, for both disbudding and dehorning procedures. The goal of this management is to create a safer environment, reduce stress on the animals during handling and transport, and facilitate easier use of feeding equipment and handling facilities.