Identifying and preventing pain during and after surgery in farm animals

Pain research in farm animals has focused on routine husbandry procedures such as dehorning; much less known about the pain associated with the other surgeries such as those required for displaced abomasum and caesarean delivery. We review the literature on pain in farm animals due to non-routine procedures including laporatomy, caesarean sections, ovariectomy and ovariohysterectomy, displaced abomasums, cannulations, vasectomy and claw removal. Where there are gaps in the farm animal literature, we describe relevant studies on wildlife, companion and lab animals. This review addresses both pain responses during surgery and the pain that animals experience in the hours and days that follow. Surgical procedures sometimes cause pain responses due to damage of somatic tissues (skin, muscle, joints, etc.) and the viscera, and there is some evidence that these pain responses differ. Overall conclusions from this review are that surgical pain in farm animals is under studied, and the resulting lack of knowledge, awareness, assessment tools and treatment protocols means that both intra-operative and post-operative pain are often under treated.