Pain is an unpleasant sensation and may arise in production animals as a result of disease, injury and routine husbandry practices. Across species, pain is a complex multidimensional experience generated by activity in neural circuits. The molecules, cells and neural circuits that drive pain sensation are present at multiple levels of the nervous system, including within peripheral nerves, the spinal cord and brain. Understanding the mechanisms underlying pain signalling at each of these levels is an essential prerequisite for rational prevention and treatment of pain in animals. This chapter addresses each of the components of “pain pathway” and how they contribute to the different dimensions of the pain experience.