Bog spavin

Last updated March 15, 2019

Bog spavin is a swelling of the tibiotarsal joint of the horse's hock which, in itself, does not cause lameness. The joint becomes distended by excess synovial fluid and/or thickened synovial tissue bringing about a soft, fluctuant swelling on the front of the joint, as well as in the medial and lateral plantar pouches. Bog spavin is generally an indication of underlying pathology within the joint.

The Tibiotarsal joint is the joint between the tibia and the tarsus.

The horse is one of two extant subspecies of Equus ferus. It is an odd-toed ungulate mammal belonging to the taxonomic family Equidae. The horse has evolved over the past 45 to 55 million years from a small multi-toed creature, Eohippus, into the large, single-toed animal of today. Humans began domesticating horses around 4000 BC, and their domestication is believed to have been widespread by 3000 BC. Horses in the subspecies caballus are domesticated, although some domesticated populations live in the wild as feral horses. These feral populations are not true wild horses, as this term is used to describe horses that have never been domesticated, such as the endangered Przewalski's horse, a separate subspecies, and the only remaining true wild horse. There is an extensive, specialized vocabulary used to describe equine-related concepts, covering everything from anatomy to life stages, size, colors, markings, breeds, locomotion, and behavior.

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.

Causes

Bog spavin is a physical finding, and does not directly create lameness. Causes include synovitis (inflammation of the lining of the joint capsule), degenerative joint disease, or excessive strain of the joint capsule. In horses younger than the age of three, most cases of bog spavin are caused by a defect in the tibiotarsal joint, while in older, fully mature horses, it is most likely because of chronic strain of the joint capsule. Infection of the joint causes a severe synovitis, and should be treated as an emergency.

Many horses with bog spavin will not be lame. However, bog spavin can be a sign that the horse has joint disease, which is a very significant finding. Usually lameness will occur if the workload of the horse is increased. Bog spavin should not be treated lightly, and it is best to have a veterinarian examine the horse to find the cause, even if the horse does not appear lame.

Unlike bone spavin, bog spavin does not show any changes to the bone itself. For this reason it is considered to be of no interest to those studying animal paleopathology (Baker and Brothwell, 1980).

Bone spavin is a bony growth within the lower hock joint of horse or cattle. It is caused by osteoarthritis, and the degree of lameness that results can be serious enough to end a horse's competitive career.

Paleopathology, also spelled palaeopathology, is the study of ancient diseases. Studying pathologies, these abnormalities in biologic individuals and systems, may be intrinsic to the system itself or caused by an extrinsic factor. Any living organism can have pathology. Studies have historically focused on humans, but there is no evidence that humans are more prone to pathologies than any other animal.

Management

A veterinarian will usually radiograph the hocks of the horse to check for bony changes as it is important to address the underlying cause of the joint distension. It's important to have a veterinarian perform an equine prepurchase exam to identify an existing condition such as a bog spavin. If the bog spavin is drained then it will simply refill unless the underlying cause has healed or been treated. In many cases it may be difficult to achieve resolution of the distension. Treatment may involve injection of corticosteroids or hyaluronan into the joint and some cases may require arthroscopic surgery. Rest or controlled exercise is often indicated.

When buying a horse, many buyers ask for an equine prepurchase exam. This serves to identify any preexisting problems which may hinder a horse’s future performance and reduce buyer risk. The inspection usually consists of four phases in which a veterinarian examines all aspects of the horse’s health.

Corticosteroids are a class of steroid hormones that are produced in the adrenal cortex of vertebrates, as well as the synthetic analogues of these hormones. Two main classes of corticosteroids, glucocorticoids and mineralocorticoids, are involved in a wide range of physiological processes, including stress response, immune response, and regulation of inflammation, carbohydrate metabolism, protein catabolism, blood electrolyte levels, and behavior.

Sources

Baker, J, and Brothwell, D. 1980. Animal Diseases in Archaeology. London: Academic Press.
King, Christine, and Mansmann, Richard. 1997. Equine Lameness. Equine Research, Inc. pp. 835-836.

External links

"Spavin, Bog". New International Encyclopedia . 1905.

The New International Encyclopedia was an American encyclopedia first published in 1902 by Dodd, Mead and Company. It descended from the International Cyclopaedia (1884) and was updated in 1906, 1914 and 1926.

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