Bog Spavin

Bog spavin is usually first seen as a swelling in two distinct locations at the back and front of the hock joint. These swellings are where the joint fluid of the top joint of the hock has increased in the sack in which it is contained and pushes out so it becomes visible. It normally occurs in horses that have poor conformation of the joints which causes extra fluid to be produced as protection against damage

Bog spavin is a symptom, and does not directly create lameness but it is an indication of an underlying condition such as 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 are caused by a defect in the joint, while in older, fully-mature horses, it is most likely because of chronic strain of the joint capsule.

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 vet examines the horse to find the cause, even if it does not appear to be lame at present.