Spavin is a term used to indicate any type of swelling, either soft or hard, that develops on or around the hock that is not related specifically to a joint injury. Many types of spavin are soft to the touch and are actually the swelling of a ligament or muscle and will not cause permanent lameness to the horse provided they are properly cared for. Any horse or foal with spavin should be checked for problems with the conformation. Often corrective shoeing, especially in young horses, will help prevent further problems with the soft and bony types of spavin.
The most common soft type of spavin includes bog spavin, which is a soft lump that usually forms down from the hock and is caused by a ligament swelling. Many horses that have sickle-hocks or hocks that are bent more than normal will have bog spavin. Ice packs and anti-inflammatories as well as rest and recovery is usually all that is needed. Corticosteroid injections may also be used to reduce swelling.
Curb and throughpin are other types of swellings along the back and inside of the hock joint that are often lumped together as spavin. The most important thing to remember is that these types of swellings are soft to the touch and are fluid filled, not bony or hard. They may be hot to the touch initially due to the increased fluid, but they do not impede the horse's ability to move long term. Usually these types of spavin are caused by conformation problems but may also occur in growing foals and then simply disappear. Soft types of spavins will benefit from treatment, rest and moderate exercise with good warm ups and cool downs to help prevent over-working of the muscle.
The more problematic types of spavin are bone spavins. Bone spavin is a new bone growth, usually due to irritation or degeneration of the joint that will result in lameness and permanent damage. Horses with poor hindquarter conformation or those that are worked or exercised on very hard surfaces are more likely to develop bone spavins. Typical signs of bone spavin include a dragging of the toe of the affected leg and decrease in stride as the horse has trouble with the normal range of motion in the hock. Usually the lameness will decrease when the horse is being exercised but then will return once the horse has been rested. Occult spavin occurs when there is no noticeable outgrowth or bony growth noticeable; rather the growth is internal.
Treatment for bony spavin will depend on the degree and severity of the growth as well as the age of the horse. In occult spavin, also known as blind spavin, corrective shoeing and careful monitoring of development may be all that is required. Rest and moderate, gradual exercise is recommended. Corticosteriods and anti-inflammatories may also be helpful in reducing swelling and any associated pain. Often in young colts and fillies once the hock has properly fused the occult or blind spavin will cease to be a problem. Regular, monitored exercise and short, moderated exercise times are important to help the body reduce the inflammation and fuse the joint as required.
X-rays can be used to determine the degree of damage caused by the new bone growth in the case of bone spavin that is noticeable. A vet can advise you on prognosis for your horse and the types of exercise or riding that will be helpful in recovery, as well as how long to limit exercise to aid in healing.