The horse's spine is incredibly important in all aspects of the horse's daily life. It is the structure that allows the horse to carry his or her weight, plus it also is necessary for the lowering and raising of the neck as well as movement of the legs. The spine of the horse is not like a humans that is very flexible and mobile. A horse's spine is more rigid and designed to be relatively inflexible to keep the horse stable and balanced. In addition the spinal cord of the horse is the protection for the spinal cord that carries nerve impulses to the body allowing movement and body functions to occur in an appropriate fashion.
When spinal cord compression occurs, the individual vertebrae that make up the spine from the skull through to the tail push up directly against one another, causing pain and varying degrees of immobility, largely dependent on where the spinal cord compression occurs. Some diseases such as Wobbler's Syndrome are directly related to spinal compression, but it can also be caused by hereditary factors, injury, diseases and congenital defects.
In most mild cases of spinal cord compression the actual damage to the spine is in the neck. This can cause changes in behavior such as a stiff neck that the horse is unwilling to turn to the sides, right up to more severe conditions where the horse cannot lower or raise his or her head to eat or drink. If the compression is closer to the withers then lack of coordination on the front quarters, staggering, falling and dragging of the front feet may be very obvious signs.
In more severe cases the horse may appear to wander or stagger on both the front and back legs and may seem unable to tell where his or her feet are landing. They may fall over objects or changes in the level of the ground and have difficulty rising.
Diagnosis of spinal compression must be done by a vet as there are many other factors that can cause the same symptoms including viral and bacterial infections such as Equine Protozoal Myeloencephalitis and traumatic injuries due to falls or accidents. X-rays and ultrasound tests as well as blood and spinal fluid tests should be completed to find out the cause of the symptoms before proceeding with treatment.
Spinal compression can be treated surgically and is effective in many cases. Unfortunately the surgery is not typically done by all vets and may require a lengthy recovery and therapy to ensure the success of the treatment. Many equine research centers and universities are now performing corrective fusion type surgeries to correct spinal compression in horses. There is about a 75% success rate with these types of surgeries, but they are costly. Since the potential for the condition to be passed on genetically in some lines is assumed, it is important to discuss the decision to breed a horse that has had a history of problems with spinal compression.