Learned behaviour
Another possibility is ‘learned’ cold-back behaviour following episodes of pathological back pain — for instance in horses who have suffered acute injury to the supraspinous ligament (the ligament that runs along the top of the spine), and have then started ridden work too early. It seems that these horses ‘learn’ that having a saddle and rider on an injured back genuinely hurts and so they begin to associate being tacked up and mounted with pain.
The danger in this line of thinking is in going a step further and concluding that horses anticipate pain even when it’s no longer there. It would be more astute to ask whether a horse who develops a cold back following recovery from a back injury has not yet fully recovered and is still in pain.
The cold-back conundrum
It is possible that all of the various causes of cold backs share pain as a common factor. If this is the case and a cold back is simply a response to pain, it begs the question as to why these horses seem to work out the problem. If they didn’t, they would just have sore backs (or soreness somewhere). Does the pain — wherever it is — go away as the horse works (and, if so, how?), or does warming up the muscles allow the horse to cope more easily with the pain? We simply don’t yet know, but there is little doubt that warmth, relaxation of muscle tension and repetitive gentle movements of joints all help the horse to loosen up, move more freely and experience less discomfort. Beyond the pathological causes (where there is a diagnosable lesion), some non-pathological reasons behind certain cold-backed horses also exist. Any restriction to normal free movement of the rib-sternum and rib-vertebra, or of the facet joints of the thoracic vertebrae, have the potential to cause cold-backed horses. The upside is that they are often correctable using chiropractic,
osteopathy and other physical mobilisation techniques. Put simply, if you can restore normal free movement to the joint(s) in question, then the cold-backed behaviour resolves, sometimes for the long term. These dysfunctions, however, all produce local muscle spasm while they are present (and muscle spasms are uncomfortable), and so there is every chance that this group of horses are similarly demonstrating cold-backed behaviour due to the presence of pain.