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ARS Home » Midwest Area » West Lafayette, Indiana » Livestock Behavior Research » Research » Publications at this Location » Publication #256368
Title: Castration induced pain in pigs and other livestock

Author
item RAULT, JEAN-LOUP - Purdue University
item Lay Jr, Donald
item Marchant, Jeremy

Submitted to: Applied Animal Behaviour Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 2/21/2011
Publication Date: 10/17/2011
Citation: Rault, J., Lay Jr, D.C., Marchant Forde, J.N. 2011. Castration induced pain in pigs and other livestock. Applied Animal Behaviour Science. 135:214-225.

Interpretive Summary: Male piglets, lambs and calves being raised for meat are often castrated to prevent unwanted breeding, make management and handling easier, decrease aggression and injury, and to improve or preserve meat quality. Many livestock producers are currently required to castrate male animals to preserve market access. The castration procedure is deemed to be painful, even in newborns which may show fewer obvious behavioral responses, and it has come under increasing scrutiny from animal well-being advocates. The exact method used to carry out castration varies depending on species. With pigs, the testicles are usually removed surgically, whereas lambs and calves are often castrated by ringing or banding, during which a tight rubber ring or elastic band is placed over the scrotum above the testicles to cut off the blood and nerve supply. The degree of pain experienced by the animal may depend on the method used and the age at which the procedure is carried out, but can be quantified using measures of stress hormones and behaviors. The use of local anesthetics and pain-killing drugs can help reduce the amount of pain being experienced by the animal, but only for as long as the drug is active. Longer-term effects of castration on the animal's welfare and the amount of chronic pain being experienced is not well known. Alternatives, such as vaccinating the animal to reduce the effect of the animal's own reproductive hormones or the rearing of intact males are being investigated and if successful, the needs for castration will diminish. However, in the meantime, castration will continue to be a normal part of husbandry procedures, subject to varying degrees of recommendation of best practice or legislation depending on country, with continued 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.

Technical Abstract: Male piglets, lambs and calves being raised for meat are often castrated to prevent unwanted breeding, make management and handling easier, decrease aggression and injury, and to improve or preserve meat quality. However, castration is also 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 and is characterized by 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 will further impact the degree of pain experienced. As alternatives, such as immuno-castration or the rearing of intact males become more prevalent, the need 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.