The hoof (pl.: hooves) is the tip of a toe of an ungulate mammal, which is covered and strengthened with a thick and horny keratin covering. [1] Artiodactyls are even-toed ungulates, species whose feet have an even number of digits; the ruminants with two digits are the most numerous, e.g. giraffe, deer, bison, cattle, goat, pigs, and sheep. [2] The feet of perissodactyl mammals have an odd number of toes, e.g. the horse, the rhinoceros, and the tapir. [3] Although hooves are limb structures primarily found in placental mammals, hadrosaurs such as Edmontosaurus possessed hoofed forelimbs. The marsupial Chaeropus also had hooves. [4]
The hoof surrounds the distal end of the second phalanx, the distal phalanx, and the navicular bone. [5] The hoof consists of the hoof wall, the bars of the hoof, the sole and frog and soft tissue shock absorption structures. [5] The weight of the animal is normally borne by both the sole and the edge of the hoof wall. Hooves perform many functions, including supporting the weight of the animal, dissipating the energy impact as the hooves strike the ground or surface, protecting the tissues and bone within the hoof capsule, and providing traction for the animal. Numerous factors can affect hoof structure and health, including genetics, hoof conformation, environmental influences, and athletic performance of the animal. The ideal hoof has a parallel hoof-pastern axis, a thick hoof wall, adequate sole depth, a solid heel base and growth rings of equal size under the coronary band. [5]
There are four layers within the exterior wall of the hoof. From the outside, a hoof is made up of the stratum externum, the stratum medium, the stratum internum and the dermis parietis. The stratum externum and the stratum medium are difficult to distinguish, the stratum externum is thin and the stratum medium is what makes up the bulk of the hoof wall. [6] Inside the hoof wall is a laminar junction, a soft tissue structure that allows the hoof to withstand the demands of force transmission it undergoes. [7] This tissue structure binds the inner surface of the hoof wall, the dermis parietis and the outer surface of the third phalanx. [7]
Most even-toed ungulates (such as sheep, goats, deer, cattle, bison and pigs) have two main hooves on each foot, together called a cloven hoof. [Note 1] Most of these cloven-hooved animals also have two smaller hooves called dewclaws a little further up the leg – these are not normally used for walking, but in some species with larger dewclaws (such as deer and pigs) they may touch the ground when running or jumping, or if the ground is soft. In the mountain goat, the dewclaw serves to provide extra traction when descending rocky slopes as well as additional drag on loose or slippery surfaces made of ice, dirt, or snow. [8] Other cloven-hooved animals (such as giraffes and pronghorns) have no dewclaws.
In some so-called "cloven-hooved" animals, such as camels, the "hoof" is not properly a hoof – it is not a hard or rubbery sole with a hard wall formed by a thick nail – instead it is a soft toe with little more than a nail merely having an appearance of a hoof.
Some odd-toed ungulates (equids) have one hoof on each foot; others have (or had) three distinct hooved or heavily nailed toes, or one hoof and two dewclaws. The tapir is a special case, having three toes on each hind foot and four toes on each front foot.
Hooves grow continuously. In nature, wild animals are capable of wearing down the hoof as it continuously grows, but captive domesticated species often must undergo specific hoof care for a healthy, functional hoof. Proper care improves biomechanical efficiency and prevents lameness. [5] If not worn down enough by use, such as in the dairy industry, hooves may need to be trimmed. However, too much wear can result in damage of the hooves, and for this reason, horseshoes and oxshoes are used by animals that routinely walk on hard surfaces and carry heavy weight. [9]
Within the equine world, the expression, "no foot, no horse" emphasizes the importance of hoof health. [10] Hoof care is important in the equine industry. [5] Problems that can arise with poor horse hoof care include hoof cracks, thrush, abscesses and laminitis. [11]
A cow hoof is cloven, or divided, into two approximately equal parts, usually called claws. [12] Approximately 95% of lameness in dairy cattle occurs in the feet. [12] Lameness in dairy cows can reduce milk production and fertility, and cause reproductive problems and suffering. For dairy farm profitability, lameness, behind only infertility and mastitis, is the third most important cow health issue. [13]
Hoof trimmers trim and care for bovine hooves, usually dairy cows. Hooves can be trimmed with a sharp knife while the cow is restrained and positioned with ropes. Professional hoof-trimming tend to use angle grinders and some type of hoof trimming crush to make the process quicker and less physically demanding on the hoof trimmer. A hoof trimmer using modern machinery may trim the hooves of more than 10,000 cows per year. [14] [15] The trimmer shapes the hooves to provide the optimal weight-bearing surface. A freshly trimmed hoof may be treated with copper sulfate pentahydrate to prevent foot rot.
Hooves have historical significance in ceremonies and games. They have been used in burial ceremonies. [16]
A horseshoe is a product designed to protect a horse hoof from wear. Shoes are attached on the palmar surface of the hooves, usually nailed through the insensitive hoof wall that is anatomically akin to the human toenail, although much larger and thicker. However, there are also cases where shoes are glued.
Perissodactyla is an order of ungulates. The order includes about 17 living species divided into three families: Equidae, Rhinocerotidae (rhinoceroses), and Tapiridae (tapirs). They typically have reduced the weight-bearing toes to three or one of the five original toes, though tapirs retain four toes on their front feet. The nonweight-bearing toes are either present, absent, vestigial, or positioned posteriorly. By contrast, artiodactyls bear most of their weight equally on four or two of the five toes: their third and fourth toes. Another difference between the two is that perissodactyls digest plant cellulose in their intestines, rather than in one or more stomach chambers as artiodactyls, with the exception of Suina, do.
Ungulates are members of the diverse clade Euungulata, which primarily consists of large mammals with hooves. Once part of the clade "Ungulata" along with the clade Paenungulata, "Ungulata" has since been determined to be a polyphyletic and thereby invalid clade based on molecular data. As a result, true ungulates had since been reclassified to the newer clade Euungulata in 2001 within the clade Laurasiatheria while Paenungulata has been reclassified to a distant clade Afrotheria. Living ungulates are divided into two orders: Perissodactyla including equines, rhinoceroses, and tapirs; and Artiodactyla including cattle, antelope, pigs, giraffes, camels, sheep, deer, and hippopotamuses, among others. Cetaceans such as whales, dolphins, and porpoises are also classified as artiodactyls, although they do not have hooves. Most terrestrial ungulates use the hoofed tips of their toes to support their body weight while standing or moving. Two other orders of ungulates, Notoungulata and Litopterna, both native to South America, became extinct at the end of the Pleistocene, around 12,000 years ago.
A claw is a curved, pointed appendage found at the end of a toe or finger in most amniotes. Some invertebrates such as beetles and spiders have somewhat similar fine, hooked structures at the end of the leg or tarsus for gripping a surface as they walk. The pincers of crabs, lobsters and scorpions, more formally known as their chelae, are sometimes called claws.
A dewclaw is a digit – vestigial in some animals – on the foot of many mammals, birds, and reptiles. It commonly grows higher on the leg than the rest of the foot, such that in digitigrade or unguligrade species, it does not make contact with the ground when the animal is standing. The name refers to the dewclaw's alleged tendency to brush dew away from grass. On dogs and cats, the dewclaws are on the inside of the front legs, similarly to a human's thumb, which shares evolutionary homology. Although many animals have dewclaws, other similar species do not, such as horses, giraffes and the African wild dog.
Laminitis is a inflammation of laminae that affects the feet of ungulates and is found mostly in horses and cattle. Clinical signs include foot tenderness progressing to inability to walk, increased digital pulses, and increased temperature in the hooves. There is also swelling in foot in some cases.Severe cases with outwardly visible clinical signs are known by the colloquial term founder, and progression of the disease will lead to perforation of the coffin bone through the sole of the hoof or being unable to stand up, requiring euthanasia.
Navicular syndrome, often called navicular disease, is a syndrome of lameness problems in horses. It most commonly describes an inflammation or degeneration of the navicular bone and its surrounding tissues, usually on the front feet. It can lead to significant and even disabling lameness.
Tendinitis/tendonitis is inflammation of a tendon, often involving torn collagen fibers. A bowed tendon is a horseman's term for a tendon after a horse has sustained an injury that causes swelling in one or more tendons creating a "bowed" appearance.
A cloven hoof, cleft hoof, divided hoof, or split hoof is a hoof split into two toes. Members of the mammalian order Artiodactyla that possess this type of hoof include cattle, deer, pigs, antelopes, gazelles, goats, and sheep.
Jaime Jackson is a former farrier, horse hoof care lecturer, author, and researcher of the wild, free roaming horses in the U.S. Great Basin. He is best known for the practice of natural hoof care first written about in The Natural Horse: Lessons from the Wild (1992). His later work "Paddock Paradise: A Guide to Natural Horse Boarding" became a foundation for the alternative boarding system also known as Track System. Jackson's work focuses around Four Pillars of Natural Horse Care.
Dr. Hiltrud Strasser is a German veterinarian, who has worked for many years on the anatomy, physiology, pathology, and rehabilitation of horses' feet. She has published papers and books on this topic since the 1980s.
A horse hoof is the lower extremity of each leg of a horse, the part that makes contact with the ground and carries the weight of the animal. It is both hard and flexible. It is a complex structure surrounding the distal phalanx of the 3rd digit of each of the four limbs, which is covered by soft tissue and keratinised (cornified) matter.
A sickle-hocked leg structure is one in which the back leg joints of an animal, usually a horse or other equine mammal, are set with too much angle, resulting in the hock also being excessively angled. This can result in uneven hoof wear, which is incredibly painful for the affected horse. If the leg joints are not set properly, there is a high chance that the back joints are also set incorrectly, resulting in a poorly conformed horse.
Foot rot, also known as foul-in-the-foot, interdigital necrobacillosis or infectious pododermatitis, is a hoof infection commonly found in sheep, goats, and cattle. As the name suggests, it rots away the foot of the animal, more specifically the area between the two toes of the affected animal. It is extremely painful and contagious. It can be treated with a series of medications, but if not treated, the whole herd can become infected. The cause of the infection in cattle is two species of anaerobic bacteria, Fusobacterium necrophorum and Bacteroides melaninogenicus. Both bacteria are common to the environment in which cattle live, and Fusobacterium is present in the rumen and fecal matter of the cattle. In sheep, F. necrophorum first invades the interdigital skin following damage to the skin, and causes interdigital lesions and slight inflammation. The second stage of the disease is marked by the invasion of the foot by the foot rot bacterium Dichelobacter nodosus, a Gram-negative anaerobe. Usually, an injury to the skin between the hooves allows the bacteria to infect the animal. Another cause of foot rot may be high temperatures or humidity, causing the skin between the hooves to crack and let the bacteria infect the foot. This is one of the reasons foot rot is such a major problem in the summer. Foot rot is easily identifiable by its appearance and foul odor. Treatment is usually with an antibiotic medication, and preventing injury to the feet is the best way to prevent foot rot.
Equine podiatry is the study and management of the equine foot based on its anatomy and function.
The coffin bone, also known as the pedal bone (U.S.), is the distal phalanx, the bottommost bone in the front and rear legs of horses, cattle, pigs and other ruminants. It is encased by the hoof capsule. In horses and other odd-toed ungulates it is the third phalanx, or "P3"; in even-toed ungulates such as cattle, it is the third and fourth. The coffin bone meets the short pastern bone or second phalanx at the coffin joint. The coffin bone is connected to the inner wall of the horse hoof by a structure called the laminar layer. The insensitive laminae coming in from the hoof wall connects to the sensitive laminae layer, containing the blood supply and nerves, which is attached to the coffin bone. The lamina is a critical structure for hoof health, therefore any injury to the hoof or its support system can in turn affect the coffin bone.
Lameness is an abnormal gait or stance of an animal that is the result of dysfunction of the locomotor system. In the horse, it is most commonly caused by pain, but can be due to neurologic or mechanical dysfunction. Lameness is a common veterinary problem in racehorses, sport horses, and pleasure horses. It is one of the most costly health problems for the equine industry, both monetarily for the cost of diagnosis and treatment, and for the cost of time off resulting in loss-of-use.
Natural hoof care is the practice of keeping horses so that their hooves are worn down naturally, or trimmed to emulate natural wear, so they do not suffer overgrowth, splitting and other disorders. Horseshoes are not used, but domesticated horses may still require trimming, exercise and other measures to maintain a natural shape and degree of wear.
The limbs of the horse are structures made of dozens of bones, joints, muscles, tendons, and ligaments that support the weight of the equine body. They include two apparatuses: the suspensory apparatus, which carries much of the weight, prevents overextension of the joint and absorbs shock, and the stay apparatus, which locks major joints in the limbs, allowing horses to remain standing while relaxed or asleep. The limbs play a major part in the movement of the horse, with the legs performing the functions of absorbing impact, bearing weight, and providing thrust. In general, the majority of the weight is borne by the front legs, while the rear legs provide propulsion. The hooves are also important structures, providing support, traction and shock absorption, and containing structures that provide blood flow through the lower leg. As the horse developed as a cursorial animal, with a primary defense mechanism of running over hard ground, its legs evolved to the long, sturdy, light-weight, one-toed form seen today.
Digital dermatitis is a disease that causes lameness in cattle. It was first discovered in Italy in 1974 by Cheli and Mortellaro. This disease is caused by a mixture of different bacteria. Anaerobic bacteria, including spirochetes of the genus Treponema, are found in the lesions associated with the infection. Digital dermatitis is different from foot rot in cattle and both conditions may occur concurrently.
Lameness, behind infertility and mastitis, is the biggest cause of economic loss to a dairy farmer (Weaver, A., 2006). Many farmers and veterinarians have used a phase that distinguished that if the animal has bad hooves then it is of no use, the most common version of this phrase is used with equines, "No hoof no horse."
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