Goats are a diverse species, and a common question arises regarding their physical characteristics, particularly horns. While many associate goats with these prominent head structures, the reality is more nuanced. Not all goats possess horns; genetics and human intervention significantly influence their development.
Horned or Polled
Most goat breeds naturally develop horns. However, some goats are born without horns due to a genetic trait known as “polled.” This dominant genetic characteristic means a goat needs only one copy of the polled gene to be hornless. Conversely, for a goat to grow horns, it must inherit two copies of the recessive horned gene.
Breeding for the polled trait can present complexities, particularly with Polled Intersex Syndrome (PIS). This syndrome is linked to the dominant polled gene; female goats homozygous for the polled gene can be infertile pseudohermaphrodites, exhibiting characteristics of both sexes. Despite this, the polled gene remains a focus in breeding programs, aimed at producing hornless animals to enhance safety and management. Both male and female goats grow horns, though females typically have smaller horns than males.
Horn Development and Purpose
Goat horns are complex, living structures composed of a bony core covered by a permanent outer sheath of keratin. Keratin, the protein found in human hair and fingernails, provides durability. Horns begin to grow from horn buds present at birth and continue growing throughout the goat’s life, forming growth rings that can indicate the animal’s age.
Horns serve multiple functions. They are used for self-defense against predators and for establishing social hierarchy within a herd through headbutting and displays of dominance. They also facilitate communication and can be used for scratching. Additionally, horns contribute to thermoregulation, helping to cool the goat’s body. Blood vessels within the bony core carry blood close to the surface, allowing heat to dissipate, which is particularly beneficial for breeds with thick coats like Angora goats.
Horns Versus Antlers
Horns and antlers are distinct biological structures. Horns, found on animals like goats, cattle, and sheep (Bovidae family), are permanent projections. They typically do not branch. Unlike antlers, horns are never shed.
Antlers, in contrast, are characteristic of the deer family (Cervidae). They are composed entirely of bone and are branched structures that are shed and regrown annually. Antlers grow from bony supporting structures called pedicels on the skull. During their growth, antlers are covered in a soft, vascular skin called “velvet,” which supplies blood and nutrients; this velvet is shed once the antler development is complete.
Managing Horns in Goats
Human intervention frequently addresses goat horns, primarily through two practices: disbudding and dehorning. Disbudding involves preventing horn growth in young kids by destroying the horn-producing cells, typically performed within the first few weeks of life, ideally between 3 and 14 days of age. This procedure is less invasive because the horn bud has not yet fused with the skull.
Dehorning, on the other hand, is the removal of existing horns from older goats. This is a more involved and painful procedure, often requiring veterinary attention and local anesthesia, as it can result in significant bleeding and expose the sinus cavity. Both disbudding and dehorning are practiced for safety reasons, reducing the risk of injury to handlers, other animals, and the goats themselves. Horned goats can accidentally injure others or become entangled in fencing.