Bog spavin is a swelling of the tibiotarsal joint of the

horse The horse (''Equus ferus caballus'') is a domesticated, one-toed, hoofed mammal. It belongs to the taxonomic family Equidae and is one of two extant subspecies of ''Equus ferus''. The horse has evolved over the past 45 to 55 million ...

hock Hock may refer to: Common meanings: * Hock (wine), a type of wine * Hock (anatomy), part of an animal's leg * To leave an item with a pawnbroker People: * Hock (surname) * Richard "Hock" Walsh (1948-1999), Canadian blues singer Other uses: * A t ...

which, in itself, does not cause lameness. The joint becomes distended by excess

synovial fluid Synovial fluid, also called synovia, elp 1/sup> is a viscous, non-Newtonian fluid found in the cavities of synovial joints. With its egg white–like consistency, the principal role of synovial fluid is to reduce friction between the articul ...

and/or thickened

synovial tissue The synovial membrane (also known as the synovial stratum, synovium or stratum synoviale) is a specialized connective tissue that lines the inner surface of capsules of synovial joints and tendon sheath. It makes direct contact with the fibrous ...

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.

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 Osteoarthritis (OA) is a type of degenerative joint disease that results from breakdown of joint cartilage and underlying bone which affects 1 in 7 adults in the United States. It is believed to be the fourth leading cause of disability in the w ...

, 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 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. Description Bone spavin is osteoart ...

, 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).

Management

A veterinarian will usually

radiograph Radiography is an imaging technique using X-rays, gamma rays, or similar ionizing radiation and non-ionizing radiation to view the internal form of an object. Applications of radiography include medical radiography ("diagnostic" and "therapeuti ...

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

corticosteroid 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 in ...

s or

hyaluronan Hyaluronic acid (; abbreviated HA; conjugate base hyaluronate), also called hyaluronan, is an anionic, nonsulfated glycosaminoglycan distributed widely throughout connective, epithelial, and neural tissues. It is unique among glycosaminogl ...

into the joint and some cases may require arthroscopic surgery. Rest or controlled exercise is often indicated.

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

* {{Cite NIE, wstitle=Spavin, Bog, short=x Equine injury and lameness