Pain mitigation and welfare

In any species the presence of pain is a welfare issue. The prevention, recognition and treatment of pain in horses involves ethical, welfare and medical knowledge. Most horses will experience acute and / or chronic pain during their lifetime. Examples of acute pain include wounds, post-operative pain (e.g., after castration), and “colic.” Examples of chronic (also referred to as maladaptive) pain include laminitis, tendon injuries and musculoskeletal diseases such as osteoarthritis. However it should be noted that there is a “continuum” where acute pain can evolve into chronic pain and some diseases may start as acute but become recurring and affect the horse long term; one example is laminitis.

By the very nature of what we expect from horses, ranging from gentle pleasure riding to participation in racing events or carrying heavy loads over long distances, it should be expected that injury resulting in pain is an occupational hazard.1 Webster stated that it may be morally acceptable to expose horses to the risk of injury through racing, but not to ignore the painful outcome of such injury.² Alleviation of pain is a welfare issue and we have an obligation to treat animals in our care as we do not want them to suffer. However treating pain is also good medicine. Pain has wide-reaching negative effects including but not limited to promoting ileus with serious outcomes (e.g., impaction), immunosuppression, delayed healing, defensive behaviors which make nursing care difficult and handling dangerous, catabolism, weight loss and adverse cardiovascular effects (e.g., tachycardia and hypertension).

It is important to anticipate pain because preventive measures are beneficial; for example administering analgesics before, during and after surgery which is referred to as preventive analgesia. We have a wide variety of analgesic drugs and techniques at our disposal to treat pain in horses, but just using these does not mean they have alleviated pain in an individual patient. To claim that pain has been treated effectively, it must be measurable. If we ask, “what is the unit of pain?” the answer is “there is none.” Recognition, assessment or measurement of pain is important as horses are unable to self-report. Recognition and assessment of pain is based on understanding normal equine behaviour and documenting what changes after a painful insult or onset of disease. This is an area where great strides have been made and we now have clinically applicable pain assessment tools which all clinicians should be encouraged to use.^3-5

Owners and veterinarians must be engaged in the prevention, recognition and treatment of pain in horses. Education of all stakeholders, the continued development of assessment tools and effective analgesic drugs and non-drug therapies are essential components of equine welfare.