Castration induced pain in pigs and other livestock

Castration of male livestock being reared for meat has long been practiced, to prevent unwanted breeding, make management and handling easier, and to improve meat quality. However, castration is a painful procedure for the animal and has increasingly come under scrutiny from animal welfare lobbyists. Depending on the species, a number of different methods are available which include surgical removal of the testes following scrotal incision, crushing of the blood and nerve supply using clamps, rubber rings or latex bands, the destruction of testicular tissue using chemicals or vaccination against hormones such as GnRH and LH that control testicular function (immuno-castration). The degree of pain experienced by the animal may depend on the method used and the age at which the procedure is carried out. This is characterized by an activation of the HPA axis, resulting in a large cortisol response, and obvious display of pain-related behaviours including abnormal posture, increased inactivity, and attention directed towards the site of injury. Use of anaesthetics and analgesics impact the degree of pain experienced. As alternatives, such as immuno-castration or the rearing of intact males become more prevalent, the needs for castration will diminish. However, in the meantime, castration will continue to be seen by many producers as a routine procedure, subject to varying degrees of recommendation of best practice or legislation depending on country, and subject to attention from animal welfare groups and policy-makers. Further science is needed to best inform all stakeholders as to the longer-term implications of castration methods on pain and welfare of individuals. Published by Elsevier B.V.