Bog spavin
Encyclopedia
Bog Spavin is a swelling of the tibiotarsal joint
Tibiotarsal joint
The Tibiotarsal joint is the joint between the tibia and the tarsus.Synovial distension of the tibiotarsal joint in the horse is known as Bog spavin....

 of the horse
Horse
The horse is one of two extant subspecies of Equus ferus, or the wild horse. It is a single-hooved 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 into the large, single-toed animal of today...

's hock
Hock (zoology)
The hock, or gambrel, is the joint between the tarsal bones and tibia of a digitigrade or unguligrade quadrupedal mammal, such as a horse, cat, or dog...

 which, in itself, does not cause lameness
Lameness (equine)
Lameness in horses and other equidae is a term used to refer to any number of conditions where the animal fails to travel in a regular and sound manner on all four feet...

. The joint becomes distended by excess synovial fluid
Synovial fluid
Synovial fluid is a viscous, non-Newtonian fluid found in the cavities of synovial joints. With its yolk-like consistency , the principal role of synovial fluid is to reduce friction between the articular cartilage of synovial joints during movement.-Overview:The inner membrane of synovial joints...

 and/or thickened synovial tissue
Synovium
Synovial membrane is the soft tissue found between the articular capsule and the joint cavity of synovial joints....

 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 of Bog Spavin

Bog Spavin is a physical finding, and does not directly create lameness
Lameness (equine)
Lameness in horses and other equidae is a term used to refer to any number of conditions where the animal fails to travel in a regular and sound manner on all four feet...

. 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 if a veterinarian examine the horse to find the cause, even if the horse does not appear lame.

Unlike bone spavin
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 of 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
Paleopathology
Paleopathology, also spelled palaeopathology, is the study of ancient diseases. It is useful in understanding the past history of diseases, and uses this understanding to predict its course in the future.- History of paleopathology :...

 (Baker and Brothwell, 1980).

Management of Bog Spavin

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
Equine prepurchase exam
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...

 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
Corticosteroid
Corticosteroids are a class of steroid hormones that are produced in the adrenal cortex. Corticosteroids are involved in a wide range of physiologic systems such as stress response, immune response and regulation of inflammation, carbohydrate metabolism, protein catabolism, blood electrolyte...

s or hyaluronan
Hyaluronan
Hyaluronan is an anionic, nonsulfated glycosaminoglycan distributed widely throughout connective, epithelial, and neural tissues...

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

Additional Notes

The tibiotarsal joint is also known as the tarsocrural joint.
Bog Spavin is also the name of the Veterinary Rock Band, Bog Spavin, from Colorado State University's Veterinary Medical School.

Sources

Baker, J, and Brothwell, D. 1980. "Animal Diseases in Archaeology". London: Academic Press.

King, Christine, BVSc, MACVSc, and Mansmann, Richard, VDM, PhD. 1997. "Equine Lameness." Equine Research, Inc. Pages 835-836.
The source of this article is wikipedia, the free encyclopedia.  The text of this article is licensed under the GFDL.
 
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