What is bone spavin? Bone spavin is a common, often painful condition of the two most distal joints of the hock (DIT and TMT); it is also called true spavin or jack spavin and is a manifestation of osteoarthritis or degenerative joint disease. The lameness associated with bone spavin usually has a slow onset with progressively worsening clinical signs.
What causes bone spavin? Bone spavin usually occurs in mature or older horses that are asked to work excessively off the hind limbs. Repeated compression and rotation of the bones (as with high speed stops and turns) and excessive tension on the ligaments and tendons is a prominent component of the whole disease process. Multiple repetitive traumatic insults (“use trauma”) to the hock as associated with day to day training, activities, and competition of these horses is a common factor in the pathogenesis of osteoarthritis.
Although some horses do not have observable changes that can be detected or measured, they still suffer from pain in the hock. When this is the case, the term blind or occult spavin is instituted. These horses display the clinical signs of bone spavin (such as pain and/or a reluctance to perform or a reluctance to perform at the previous level), but not all of the documentable changes are necessarily seen. Conformation of the horse is also a factor in the development of bone spavin. Horses with sickle hocks (increased angle of