The term pain relief is used throughout this document to mean the reduction of behavioural and
physiological responses by an animal to a painful stimulus to a level judged to be reasonable. Drugs
are the common means by which pain relief is achieved; they act in various ways on the peripheral
and central nervous systems and may be applied topically or by injection. The range of drugs
available for use in cattle, and the effectiveness and duration of pain relief provided is often limited.