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Alleviating the pain caused by the castration of cattle
The Veterinary Journal The Veterinary Journal 173 (2007) 245–247 www.elsevier.com/locate/tvjl
Guest Editorial
Alleviating the pain caused by the castration of cattle
The castration of bulls to produce draft oxen, making cattle safer and easier to manage, preventing unwanted mating and modifying carcass characteristics, is an ancient practice. All physical methods of castration cause pain and veterinary interest in alleviating this pain is not new. In 1929, Campbell recommended that the second crush of the Burdizzo be distal to the first so as to reduce pain and in 1935 Miller wrote to justify castration to the ÔhumanitarianÕ in the second edition of BlackÕs Veterinary Dictionary. Individual veterinarians dislike particular methods of castration. Cox (1977) and Clarke-Lewis (1977) recommended that the Burdizzo be banned because of the pain it caused (the latter likened it to a gin trap), and Weaver (1986), in his excellent textbook on bovine surgery, condemned rubber ring castration because of the post-operative pain it caused. However, most non-clinical attempts at quantifying the pain caused by castration in calves, using physiological and immunological responses and behaviour, were carried out in the last 20 years (Stafford and Mellor, 2005). In these studies local anaesthesia and/or systemic analgesia were used to identify the physiological responses and behaviours caused by the pain of castration. The pain caused by different methods of castration was compared and methods of alleviating this pain investigated (Stafford et al., 2002). The paper by Susann Thu¨er and colleagues published in this issue of The Veterinary Journal continues this mode of research (Thu¨er et al., 2007). They compared the behaviour and plasma cortisol responses to two methods of castration (rubber ring and Burdizzo) with and without local anaesthesia. They found that the plasma cortisol response to Burdizzo castration was greater initially than the response to rubber ring castration but the response lasted longer after the latter technique had been used. These results suggest that the pain experienced during and for the first hour or so after Burdizzo castration is greater than that caused by rubber ring castration but that the ring technique probably causes 1090-0233/$ - see front matter Ó 2005 Elsevier Ltd. All rights reserved. doi:10.1016/j.tvjl.2005.11.002
greater pain for the next few hours. The plasma cortisol response to ring and surgical castration are similar (Stafford et al., 2002). The overall pain caused by Burdizzo in the hours following castration, as defined by the integrated plasma cortisol, is less than that caused by surgery or ring castration (Molony et al., 1995; Stafford et al., 2002). Thu¨er and colleagues also found that calves which had been castrated by rubber ring responded to scrotal palpation in a manner suggestive of pain for eight weeks while those castrated by Burdizzo stopped responding after two weeks (Thu¨er et al., 2007). They concluded that the Burdizzo method was preferable to the rubber ring because of the long term pain experienced by calves castrated using rings. This conclusion is supported by the observations of Molony et al. (1995) who found that behaviour returned to normal following surgical, Burdizzo and rubber ring castration after 9, 15 and 45 days, respectively. Thu¨er et al. (2007) found that local anaesthesia given into the spermatic cord and scrotal neck reduced the pain related behaviours during Burdizzo castration. However local anaesthesia given into the testes and scrotum does not reduce the plasma cortisol response to Burdizzo or surgical castration but eliminates that following ring castration (Stafford et al., 2002). To eliminate the plasma cortisol response, and by inference the pain experienced, in the 8 h following surgical or Burdizzo castration, it is necessary to use local anaesthetic, given into the scrotum or its contents, combined with a systemic analgesic such as a non-steroidal anti-inflammatory drug (NSAID) (Stafford et al., 2002). The epidural administration of xylazine acts as an effective analgesic for about 80% of adult bulls (Caulkett et al., 1993). Pain is not the only issue to be considered when choosing a method of castration. Side-effects (infection, haemorrhage), wound healing, the ease of carrying out the procedure, cost and access to local anaesthetics
246
Guest Editorial / The Veterinary Journal 173 (2007) 245–247
and analgesics, and the availability of equipment and trained staff are important. Certainty of castration is a priority and failure rates are higher with Burdizzo castration than with ring or surgery (Kent et al., 1996). Failure will result in some cattle having to be castrated a second time and may cause unwanted mating, often of immature heifers, with all the welfare problems both these issues involve. Beef production from bulls is possible but there are welfare issues with bull beef production – notably injuries, which may be serious, from fighting and riding. Alternative methods of castration such as chemical or immuno-castration are not useful at this time. So what castration protocol can one recommend? The decision depends upon what is practicable, what level of analgesia is possible and how one interprets the significance of acute versus longer term pain for the calf. Cattle management practices may determine the age at castration. Robertson et al. (1994) showed that younger calves experience less pain than older animals, but it may not be possible to castrate young calves on extensive beef properties where calves may not be mustered until they are five or six months of age when they are castrated, vaccinated, marked (branded, ear tagged, ear notched) and treated for parasites. Rubber rings are too small for calves this age, Burdizzo castration is too slow, and generally these calves are castrated surgically without analgesia. Recently a castration device using a latex ring band has been developed to castrate large cattle. However, this method causes greater reduction in weight gain than surgical castration in the months following castration (Knight et al., 2000) suggesting that it is the more painful procedure. On intensive cattle farms calves are frequently handled from an early age and can be castrated in the first days or weeks of life by whatever method. The cost of analgesic drugs and legal restrictions on who can use veterinary drugs may make pain control difficult for many farmers, and the cost of employing a veterinarian to carry out a basic husbandry practices like castration may be prohibitive (Stafford et al., 2005). In any case farm animal veterinarians are rare in many communities. Therefore in many parts of the world and in many production systems, pain alleviation for cattle subject to castration is unlikely to happen in the near future. It is nevertheless important that wealthy countries do not use this lack of opportunity to hamper trade thus using animal welfare as a form of cultural and economic imperialism. Surgical castration of calves, the method favoured by many veterinarians, has advantages with regard to long term pain but local anaesthesia plus a systemic analgesic, or epidural anaesthesia is needed to alleviate the pain it causes in the 8 h immediately following the castration. Surgery causes more pain in this period than Burdizzo but the certainty and simplicity of the procedure has much to recommend it. Rubber ring castration
is simple, cheap and effective on young calves and the pain caused by it in the following 8 h can be alleviated by local anaesthesia given into the testes and scrotum, but the long term pain it causes is an important issue. Indeed understanding the significance of long term pain is the most important topic for those investigating the pain caused by surgery in all animals. It may be that after some hours or days, castrated calves experience irritation rather than pain. If, however, calves continue to experience pain over the weeks following castration it is important to determine how severe is this pain and whether it differs with the various methods of castration. If it is shown that the pain is significant we will need to develop protocols to prevent this pain or to alleviate it on an ongoing basis for some weeks after castration. At present this is neither practicable nor economically possible. Thus while we can gauge the relative severity of the pain caused by different methods of castration in the hours following castration and know how to lessen it, there remains a number of important questions relating to our understanding of the experience of the long lasting pain caused by castration and its alleviation. Kevin Stafford Animal Welfare Science and Bioethics Centre, Institute of Veterinary Animal and Bioethics Centre, Massey University, Palmerston North, New Zealand E-mail address: K.J.Staff[email protected]
References Campbell, W.A., 1929. Castration by the Burdizzo. The Veterinary Record 9, 81. Caulkett, N.A., MacDonald, D.G., Janzen, E.D., Cribb, P.N., Fretz, P.B., 1993. Xylazine hydrochloride epidural analgesia – a method of providing sedation and analgesia to facilitate castration of mature bulls. Compendium of Continuing Education for Practicing Veterinarians 15, 1155–1159. Clarke-Lewis, A.V., 1977. Bloodless castrator. The Veterinary Record 100, 215. Cox, J.E., 1977. Bloodless castrators. The Veterinary Record 100, 431– 432. Kent, J.E., Thrusfield, I.S., Robertson, I.S., Molony, V., 1996. Castration of calves; a study of the methods used by farmers in the United Kingdom. The Veterinary Record 138, 384–387. Knight, T.W., Cosgrove, G.P., Death, A.F., Anderson, C.B., 2000. Effect of method of castrating bulls on their growth rate and liveweight. New Zealand Journal of Agricultural Research 43, 187– 192. Miller, W.C., 1935. BlackÕs Veterinary Dictionary. A & C Black Ltd., London, UK. Molony, V., Kent, J.E., Robertson, I.S., 1995. Assessment of acute and chronic pain after different methods of castration of calves. Applied Animal Behaviour Science 46, 33–48. Robertson, I.S., Kent, J.E., Molony, V., 1994. Effects of different methods of castration on behaviour and plasma cortisol in calves of three ages. Research in Veterinary Science 56, 8–17. Stafford, K.J., Mellor, D.J., Todd, S.E., Bruce, R.A., Ward, R.N., 2002. Effects of local anaesthesia or local anaesthesia plus a non-steroidal
Guest Editorial / The Veterinary Journal 173 (2007) 245–247 anti-inflammatory drug on the acute cortisol response of calves to five different methods of castration. Research in Veterinary Science 73, 61–70. Stafford, K.J., Mellor, D.J., 2005. The welfare significance of the castration of cattle: a review. New Zealand Veterinary Journal 53, 271–278. Stafford, K.J., Mellor, D.J., Dooley, A.E., Smeaton, D., McDermott, A., 2005. The cost of alleviating the pain caused by the
247
castration of beef calves. Proceedings of the New Zealand Society of Animal Production 65, 123–126. Thu¨er, S., Mellema, S., Doherr, M.G., Wechsler, B., Nuss, K., Steiner, A., 2007. Effect of local anaesthesia on short- and longterm pain induced by two bloodless castration methods in calves. The Veterinary Journal 173, 333–342. Weaver, A.D., 1986. Bovine Surgery and Lameness. Blackwell Scientific Publications, UK.
Guest Editorial
Alleviating the pain caused by the castration of cattle
The castration of bulls to produce draft oxen, making cattle safer and easier to manage, preventing unwanted mating and modifying carcass characteristics, is an ancient practice. All physical methods of castration cause pain and veterinary interest in alleviating this pain is not new. In 1929, Campbell recommended that the second crush of the Burdizzo be distal to the first so as to reduce pain and in 1935 Miller wrote to justify castration to the ÔhumanitarianÕ in the second edition of BlackÕs Veterinary Dictionary. Individual veterinarians dislike particular methods of castration. Cox (1977) and Clarke-Lewis (1977) recommended that the Burdizzo be banned because of the pain it caused (the latter likened it to a gin trap), and Weaver (1986), in his excellent textbook on bovine surgery, condemned rubber ring castration because of the post-operative pain it caused. However, most non-clinical attempts at quantifying the pain caused by castration in calves, using physiological and immunological responses and behaviour, were carried out in the last 20 years (Stafford and Mellor, 2005). In these studies local anaesthesia and/or systemic analgesia were used to identify the physiological responses and behaviours caused by the pain of castration. The pain caused by different methods of castration was compared and methods of alleviating this pain investigated (Stafford et al., 2002). The paper by Susann Thu¨er and colleagues published in this issue of The Veterinary Journal continues this mode of research (Thu¨er et al., 2007). They compared the behaviour and plasma cortisol responses to two methods of castration (rubber ring and Burdizzo) with and without local anaesthesia. They found that the plasma cortisol response to Burdizzo castration was greater initially than the response to rubber ring castration but the response lasted longer after the latter technique had been used. These results suggest that the pain experienced during and for the first hour or so after Burdizzo castration is greater than that caused by rubber ring castration but that the ring technique probably causes 1090-0233/$ - see front matter Ó 2005 Elsevier Ltd. All rights reserved. doi:10.1016/j.tvjl.2005.11.002
greater pain for the next few hours. The plasma cortisol response to ring and surgical castration are similar (Stafford et al., 2002). The overall pain caused by Burdizzo in the hours following castration, as defined by the integrated plasma cortisol, is less than that caused by surgery or ring castration (Molony et al., 1995; Stafford et al., 2002). Thu¨er and colleagues also found that calves which had been castrated by rubber ring responded to scrotal palpation in a manner suggestive of pain for eight weeks while those castrated by Burdizzo stopped responding after two weeks (Thu¨er et al., 2007). They concluded that the Burdizzo method was preferable to the rubber ring because of the long term pain experienced by calves castrated using rings. This conclusion is supported by the observations of Molony et al. (1995) who found that behaviour returned to normal following surgical, Burdizzo and rubber ring castration after 9, 15 and 45 days, respectively. Thu¨er et al. (2007) found that local anaesthesia given into the spermatic cord and scrotal neck reduced the pain related behaviours during Burdizzo castration. However local anaesthesia given into the testes and scrotum does not reduce the plasma cortisol response to Burdizzo or surgical castration but eliminates that following ring castration (Stafford et al., 2002). To eliminate the plasma cortisol response, and by inference the pain experienced, in the 8 h following surgical or Burdizzo castration, it is necessary to use local anaesthetic, given into the scrotum or its contents, combined with a systemic analgesic such as a non-steroidal anti-inflammatory drug (NSAID) (Stafford et al., 2002). The epidural administration of xylazine acts as an effective analgesic for about 80% of adult bulls (Caulkett et al., 1993). Pain is not the only issue to be considered when choosing a method of castration. Side-effects (infection, haemorrhage), wound healing, the ease of carrying out the procedure, cost and access to local anaesthetics
246
Guest Editorial / The Veterinary Journal 173 (2007) 245–247
and analgesics, and the availability of equipment and trained staff are important. Certainty of castration is a priority and failure rates are higher with Burdizzo castration than with ring or surgery (Kent et al., 1996). Failure will result in some cattle having to be castrated a second time and may cause unwanted mating, often of immature heifers, with all the welfare problems both these issues involve. Beef production from bulls is possible but there are welfare issues with bull beef production – notably injuries, which may be serious, from fighting and riding. Alternative methods of castration such as chemical or immuno-castration are not useful at this time. So what castration protocol can one recommend? The decision depends upon what is practicable, what level of analgesia is possible and how one interprets the significance of acute versus longer term pain for the calf. Cattle management practices may determine the age at castration. Robertson et al. (1994) showed that younger calves experience less pain than older animals, but it may not be possible to castrate young calves on extensive beef properties where calves may not be mustered until they are five or six months of age when they are castrated, vaccinated, marked (branded, ear tagged, ear notched) and treated for parasites. Rubber rings are too small for calves this age, Burdizzo castration is too slow, and generally these calves are castrated surgically without analgesia. Recently a castration device using a latex ring band has been developed to castrate large cattle. However, this method causes greater reduction in weight gain than surgical castration in the months following castration (Knight et al., 2000) suggesting that it is the more painful procedure. On intensive cattle farms calves are frequently handled from an early age and can be castrated in the first days or weeks of life by whatever method. The cost of analgesic drugs and legal restrictions on who can use veterinary drugs may make pain control difficult for many farmers, and the cost of employing a veterinarian to carry out a basic husbandry practices like castration may be prohibitive (Stafford et al., 2005). In any case farm animal veterinarians are rare in many communities. Therefore in many parts of the world and in many production systems, pain alleviation for cattle subject to castration is unlikely to happen in the near future. It is nevertheless important that wealthy countries do not use this lack of opportunity to hamper trade thus using animal welfare as a form of cultural and economic imperialism. Surgical castration of calves, the method favoured by many veterinarians, has advantages with regard to long term pain but local anaesthesia plus a systemic analgesic, or epidural anaesthesia is needed to alleviate the pain it causes in the 8 h immediately following the castration. Surgery causes more pain in this period than Burdizzo but the certainty and simplicity of the procedure has much to recommend it. Rubber ring castration
is simple, cheap and effective on young calves and the pain caused by it in the following 8 h can be alleviated by local anaesthesia given into the testes and scrotum, but the long term pain it causes is an important issue. Indeed understanding the significance of long term pain is the most important topic for those investigating the pain caused by surgery in all animals. It may be that after some hours or days, castrated calves experience irritation rather than pain. If, however, calves continue to experience pain over the weeks following castration it is important to determine how severe is this pain and whether it differs with the various methods of castration. If it is shown that the pain is significant we will need to develop protocols to prevent this pain or to alleviate it on an ongoing basis for some weeks after castration. At present this is neither practicable nor economically possible. Thus while we can gauge the relative severity of the pain caused by different methods of castration in the hours following castration and know how to lessen it, there remains a number of important questions relating to our understanding of the experience of the long lasting pain caused by castration and its alleviation. Kevin Stafford Animal Welfare Science and Bioethics Centre, Institute of Veterinary Animal and Bioethics Centre, Massey University, Palmerston North, New Zealand E-mail address: K.J.Staff[email protected]
References Campbell, W.A., 1929. Castration by the Burdizzo. The Veterinary Record 9, 81. Caulkett, N.A., MacDonald, D.G., Janzen, E.D., Cribb, P.N., Fretz, P.B., 1993. Xylazine hydrochloride epidural analgesia – a method of providing sedation and analgesia to facilitate castration of mature bulls. Compendium of Continuing Education for Practicing Veterinarians 15, 1155–1159. Clarke-Lewis, A.V., 1977. Bloodless castrator. The Veterinary Record 100, 215. Cox, J.E., 1977. Bloodless castrators. The Veterinary Record 100, 431– 432. Kent, J.E., Thrusfield, I.S., Robertson, I.S., Molony, V., 1996. Castration of calves; a study of the methods used by farmers in the United Kingdom. The Veterinary Record 138, 384–387. Knight, T.W., Cosgrove, G.P., Death, A.F., Anderson, C.B., 2000. Effect of method of castrating bulls on their growth rate and liveweight. New Zealand Journal of Agricultural Research 43, 187– 192. Miller, W.C., 1935. BlackÕs Veterinary Dictionary. A & C Black Ltd., London, UK. Molony, V., Kent, J.E., Robertson, I.S., 1995. Assessment of acute and chronic pain after different methods of castration of calves. Applied Animal Behaviour Science 46, 33–48. Robertson, I.S., Kent, J.E., Molony, V., 1994. Effects of different methods of castration on behaviour and plasma cortisol in calves of three ages. Research in Veterinary Science 56, 8–17. Stafford, K.J., Mellor, D.J., Todd, S.E., Bruce, R.A., Ward, R.N., 2002. Effects of local anaesthesia or local anaesthesia plus a non-steroidal
Guest Editorial / The Veterinary Journal 173 (2007) 245–247 anti-inflammatory drug on the acute cortisol response of calves to five different methods of castration. Research in Veterinary Science 73, 61–70. Stafford, K.J., Mellor, D.J., 2005. The welfare significance of the castration of cattle: a review. New Zealand Veterinary Journal 53, 271–278. Stafford, K.J., Mellor, D.J., Dooley, A.E., Smeaton, D., McDermott, A., 2005. The cost of alleviating the pain caused by the
247
castration of beef calves. Proceedings of the New Zealand Society of Animal Production 65, 123–126. Thu¨er, S., Mellema, S., Doherr, M.G., Wechsler, B., Nuss, K., Steiner, A., 2007. Effect of local anaesthesia on short- and longterm pain induced by two bloodless castration methods in calves. The Veterinary Journal 173, 333–342. Weaver, A.D., 1986. Bovine Surgery and Lameness. Blackwell Scientific Publications, UK.