Topical anaesthesia alleviates short-term pain of castration and tail docking in lambs

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PRODUCTION ANIMALS Topical anaesthesia alleviates short-term pain of castration and tail docking in lambs PRODUCTION ANIMALS avj_546 67..74 S Lomax,a H Dickson,a M Sheila,b and PA Windsora* these procedures cause acute pain and stress,2–7 they are routinely Objective To investigate the effect of a topical anaesthetic for- conducted without analgesia. Despite their justification for animal mulation on pain alleviation, wound healing and systemic levels of health, production and management reasons, there is growing local anaesthetic actives in lambs undergoing castration and tail docking. concern for the welfare of animals undergoing these procedures. In the European Union, for example, some countries have passed legis- Design Three placebo-controlled and/or randomised experi- lation banning piglet or lamb castration unless analgesia is used. In ments were conducted using three groups of Merino lambs (n = 62, other countries, supermarket chains are refusing to take products 68 and 19) undergoing routine castration and tail docking. from pigs unless they were castrated with analgesia. In the United Procedure Surgical castration, with either surgical or hot-iron tail Kingdom, the Farm Animal Welfare Council has released a new report docking, was performed with and without the application of topical calling for urgent action to develop effective analgesia for lambs anaesthetic (Tri-Solfen®) or placebo. The effects of this procedure undergoing castration and tail docking.8 These developments reflect were compared with those of rubber ring castration and tail the growing demand for humane management of livestock through- docking, and of the handled but unmarked controls. Wound pain out the world and set a challenge to develop effective methods of pain was assessed

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ough- docking, and of the handled but unmarked controls. Wound pain out the world and set a challenge to develop effective methods of pain was assessed using calibrated Von-Frey monofilaments over a 4-h alleviation that are practical and applicable to farming operations. period, pain-related behaviour was assessed over 5 h, wound Tri-Solfen® (Bayer Animal Health, Gordon, NSW, Australia) is a healing was assessed at 14 and 28 days, and the plasma levels of ‘farmer applied’ spray-on topical anaesthetic formulation of lignocaine and bupivacaine were determined. lignocaine (as the hydrochloride: 40.6 g/L), bupivacaine (as the hydro- Results Rapid and up to 4 h primary hyperalgesia developed fol- chloride: 4.5 g/L), adrenalin (as a tartrate: 24.8 mg/L) and cetrimide lowing surgical castration and tail docking in the untreated and (5.0 g/L in a gel base). It has been reported that topical anaesthesia placebo-treated lambs. It was absent in the castration wounds, and with Tri-Solfen is highly effective in alleviating pain associated with significantly reduced in the tail-docking wounds, of the treated mulesing and improves wound healing.9 In the present studies we lambs. Hot-iron docking was associated with mild and transient investigated the potential for topical anaesthesia to alleviate the pain secondary hyperalgesia, which was abolished by the topical anaes- associated with castration and tail docking in sheep. thesia. There was a significant reduction in pain-related behaviours in treated lambs, which were not significantly different in their Materials and methods behaviour to the sham-operation handled controls. Plasma lignocaine and bupivacaine levels were below the toxic thresholds Two experiments were performed on ram lambs undergoing routine in all

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ntrols. Plasma lignocaine and bupivacaine levels were below the toxic thresholds Two experiments were performed on ram lambs undergoing routine in all tested lambs. tail docking and castration in commercial flocks in the Central Table- Conclusion Topical anaesthesia alleviates wound pain and sig- lands and Southern Highlands of New South Wales, Australia. Lambs nificantly reduces pain-related behaviours in lambs undergoing were aged 6 to 12 weeks with a mean initial body weight of 14.48 kg surgical castration plus surgical or hot-iron tail docking, without a (⫾2.8 kg) and consisted of 62 F1 Merino ¥ South African Mutton negative effect on wound healing or a risk of systemic toxicity. Merino lambs (Central Tablelands flock) and 68 finewool Merino lambs (Southern Highlands flock) born in the winter of 2007. Lambs Keywords analgesia; castration; lambs; pain; tail docking; topical were divided into eight treatment groups to examine surgical castra- anaesthesia; welfare tion plus surgical or hot-iron (HI) tail docking, (performed without Tri-Solfen or with Tri-Solfen or placebo), rubber ring castration and Abbreviations HI, hot iron; LT, light touch sensation; NRS, tail docking, and sham procedure in which lambs were handled only numerical rating scale; P, pain sensation but remained uncastrated or tail-docked (Table 1). In a third experi- Aust Vet J 2010;88:67–74 doi: 10.1111/j.1751-0813.2009.00546.x ment, for determining the plasma levels of lignocaine and bupivacaine after treatment with the topical anaesthetic, blood samples were col- lected from finewool Merino lambs aged 6 to 12 weeks from a com- L amb marking, which includes castration of male lambs and tail mercial flock in the Southern Highlands, NSW, undergoing routine docking of male and female lambs

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ing, which includes castration of male lambs and tail mercial flock in the Southern Highlands, NSW, undergoing routine docking of male and female lambs is a routine husbandry tail docking and castration (n = 15) or mulesing, tail docking and procedures performed annually on between 31 and 34 million castration (n = 4). lambs in Australia,1 and many more throughout the world. Although General management and marking *Correspondence author. On the day of each experiment lambs from each flock were yarded and a Faculty of Veterinary Science, University of Sydney, PMB 3, Camden, New South Wales 2570, Australia; pwindsor@camden.usyd.edu.au drafted into a holding yard. They were then selected at random, b Animal Ethics Pty Ltd, Yarra Glen, Victoria, Australia weighed, ear-tagged and placed in marking cradles. In experiments 1 © 2010 University of Sydney Australian Veterinary Journal Volume 88, No 3, March 2010 67 PRODUCTION ANIMALS Table 1. Treatment groups and total numbers of lambs in each group in experiments 1 and 2 Group Castration Tail-docking Treatment Direct wound Pain-related behaviour PRODUCTION ANIMALS method method sensory assessment assessment (n) (n) 1 Knife Knife Untreated 11 11 2 Knife Knife Tri-Solfen 11 11 3 Knife Knife Placebo 11 11 4 Knife Hot iron Untreated 8 8 5 Knife Hot iron Tri-Solfen 8 8 6 Knife Hot iron Placebo 8 0 7 Rubber ring Rubber ring Untreated 0 12 8 Control Control Untreated 0 12 and 2, lambs were allocated sequentially to the treatment groups listed second elastrator ring was applied to the tail at the recommended in Table 1, but the order of treatments was reversed in experiment 2. position between coccygeal vertebrae 2 and 3. The first 35 to 38 lambs on each property on the day of the experiment Method of surgical castration and

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position between coccygeal vertebrae 2 and 3. The first 35 to 38 lambs on each property on the day of the experiment Method of surgical castration and topical anaesthetic or were assigned to behavioural observations. They were allocated to a placebo application Surgical castration was performed using a clean, sharp surgical knife. treatment group, treated accordingly, then were transferred in their The distal skin of the scrotum was excised, exposing the testes, which treatment groups to 5-m2 outdoor pastured observation yards away were individually extracted from the scrotum by traction, exposing from visual and auditory stimuli. Pain-related behaviour assessments the spermatic cord. Each testis was removed by incising the spermatic were performed by a trained observer, who was unaware of the treat- cord approximately 10 cm proximal to the head of the epididymis. In ment group strategy, using a numerical rating scale (NRS) at 5 and groups receiving topical anaesthetic or placebo treatment, Tri-Solfen 30 min and 1, 2, 3, 4 and 5 h after the procedures. or placebo gel (which consisted of the base gel without local anaes- The next 27 to 30 lambs on the day of the experiment were allocated thetic or vasoconstrictor compounds) was applied to each of the to wound pain assessments. They were assigned to treatment groups exposed spermatic cords proximal to the site of incision, prior to and prior to castration and tail docking their responses to light touch removal of the testis, by inserting the nozzle of the spray gun along the (LT) and pain (P) stimulation of the intact skin on the scrotum and tail length of the cord as far into the scrotal wound as possible and apply- was assessed using Von-Frey monofilaments as previously described.9 ing 1.5 mL of the Tri-Solfen or

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s far into the scrotal wound as possible and apply- was assessed using Von-Frey monofilaments as previously described.9 ing 1.5 mL of the Tri-Solfen or placebo to liberally coat the spermatic After castration and docking, (with or without Tri-Solfen or placebo cord as the applicator was withdrawn. An additional 1.5 mL of Tri- application), lambs remained in the cradle for 1 min and their Solfen or placebo was applied to the cut edge of the skin wound and responses to LT and P stimulation of the tail and scrotal wounds were the scrotal sac. The technique ensured that both the cord tissue that assessed by two observers who were unaware which treatment strategy retracted into the wound after removal of the testis and the skin of the (Tri-Solfen or placebo) had been used. Lambs were then transferred to scrotal wound were well coated with the anaesthetic or placebo agent. a small holding yard in a mixed treatment group and returned to the lamb cradle for repeat assessments at 2 and 4 h following the proce- Method of surgical and HI tail docking dures. After completion of assessments, lambs were returned to their Surgical tail docking was performed using a cleaned, sharpened sur- dams at pasture. gical lamb-marking knife, incising at the recommended position between coccygeal vertebrae 2 and 3. Wound healing was assessed at 2 and 4 weeks. Lambs were re-yarded, weighed and placed in the cradle where their wounds were inspected The HI technique for tail docking used a gas tail-docking knife that and palpated by a registered specialist veterinarian (pathobiology). had been preheated to the correct temperature to efficiently seal the coccygeal blood vessels. The skin of the tail was pushed towards the lamb’s body to locate the correct position between coccygeal vertebrae

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y seal the coccygeal blood vessels. The skin of the tail was pushed towards the lamb’s body to locate the correct position between coccygeal vertebrae Assessment of pain-related behaviour 2 and 3 and the tail elevated to avoid burning of the perineum. The Pain-related behaviour was assessed using the NRS developed previ- lever of the knife was squeezed and after 2 s the tail was severed. ously9 and modified by a combination of field observations and pub- lished reports of behavioural changes in response to castration and/or tail docking.6–11 A trained observer (animal scientist blinded to treat- Method of rubber ring castration and tail docking ment) observed the lambs at various time points after marking. Indi- Details of all procedural and treatment strategies are shown in Table 1. vidual lambs were given a score between 0 and 3: 0 = no pain-related Ring castration involved the application of an elastrator rubber ring behaviour; 1 = mildly abnormal posture, gait or behaviour, such as around the neck of the scrotum proximal to the testes in order to mild kyphosis without hyperextension of hindlegs, ventral recum- obstruct blood flow to the testes and cause ischaemic necrosis. A bency with hindlegs partially extended or mild stiffening of gait 68 Australian Veterinary Journal Volume 88, No 3, March 2010 © 2010 University of Sydney PRODUCTION ANIMALS without overt limping or leg dragging; 2 = moderately abnormal Statistical analysis posture, gait or behaviour, such as ‘statue standing’ with head down Data were analysed using SPSS version 14.0® (SPSS Inc., Chicago, IL, PRODUCTION ANIMALS and prominent kyphosis, moderate stiffening or slowing of gait or USA), and Genstat® version 10.0 (VSN International, UK 2007). Box- hyperextension and/or abduction of

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phosis, moderate stiffening or slowing of gait or USA), and Genstat® version 10.0 (VSN International, UK 2007). Box- hyperextension and/or abduction of hindlegs, ventral recumbency plots were examined and one-way analysis of variance was used to with hindlegs fully extended; 3 = displaying severely abnormal measure the short-term effects of treatment groups for which there posture, gait or behaviour, such as marked agitation with twisting or was variation. Residual maximum likelihood estimation linear mixed writhing, high frequency of postural change from lying to kneeling or models analyses were used to analyse NRS scores from behavioural standing, distressed vocalisation, lateral or prostrate lying, kneeling, and sensitivity-testing observations. Post-hoc pair-wise comparisons dog sitting or tremors, shaking or lip curling. were performed for analyses in which the between group comparison was significant. For all statistical calculations, P < 0.005 was consid- ered statistically significant. Direct wound sensory assessment Von-Frey monofilaments are calibrated to bend at predetermined This research program was approved by the Animal Ethics Committee pressures to provide repeatable LT (10N) or P (75N) stimulation, as of the University of Sydney and conformed to the provisions of the previously described.9 They were used to perform direct sensory Declaration of Helsinki (2000). testing at seven predetermined sites on the cut skin edge of the scrotal and tail wounds and at four sites on the intact skin surrounding the Results wounds to determine the lambs’ responses to LT and P stimulation Weather conditions before and up to 4 h after castration and tail docking. During experiment 1 the weather was cool and overcast, with an Evidence of local anaesthesia

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s before and up to 4 h after castration and tail docking. During experiment 1 the weather was cool and overcast, with an Evidence of local anaesthesia (diminished response to LT and P stimu- average temperature of 13°C, during experiment 2 it was cool and fine, lation), allodynia (heightened response to LT stimuli) and/or primary with an average temperature of 10°C and no fly activity and for experi- and secondary hyperalgesia (heightened response to P stimulus ment 3 it was warm and dry at 19°C, with moderate fly activity. directly in the damaged tissue or in surrounding undamaged tissue, Morbidity, mortality and wound inspection respectively) was assessed at each site. Responses were scored by Clinical signs of tetanus were not observed and none of the lambs monitoring induced involuntary motor reflexes in the rump and head, died. Direct inspection and wound palpation identified 3 lambs with which were graded by vigour. Rump response scores were graded as: abscess formation in the scrotal sac and 13 lambs with increased 0 = no response; 1 = minor involuntary motor responses such as local firmness and thickening of the cord, interpreted as a subacute to skin twitch, subcutaneous muscle twitch or anal contraction; 2 = chronic inflammatory or scirrhous cord reaction at 14 days after the partial rump withdrawal reflex, such as multiple subcutaneous muscle surgical procedure. There was no significant difference in abscess group contraction and/or lifting of the tail; 3 = full rump withdrawal formation and scirrhous cord reaction according to treatment. Even at reflex with lifting of the rump off the cradle. Facial response scores 4 weeks the majority of the lambs treated with rubber rings still had were graded as: 0 = no response; 1 = minor facial

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cradle. Facial response scores 4 weeks the majority of the lambs treated with rubber rings still had were graded as: 0 = no response; 1 = minor facial ‘awareness’, such as their scrotums and tails attached, although the tissues were cold, eye widening or blinking or nasal flaring; 2 = partial startle reflex of shrunken and firm, indicative of ischaemic necrosis. In many cases the head, such as slight lifting of the snout or partial head rotation; there was reddening and swelling of the skin immediately proximal to 3 = full startle reflex of the head, resulting in a major movement such the ring, accompanied by a small amount of yellow to greenish as lifting head off the cradle, full head jerk or full head rotation. Scores exudate, suggesting focal inflammation and minor infection. for each site were added to achieve a total score for each lamb. Total scores were calculated out of 24 for peri-wound sensitivity and out of Direct sensory testing of the castration wound and 42 for direct wound sensitivity. surrounding skin Before surgical castration. There was little response to LT or P stimulation of the intact skin of the scrotal area prior to castration. Plasma lignocaine and bupivacaine analyses Mean response from the four testing sites (maximum possible score In experiment 3, lambs were selected at random, placed in the cradle 24) was ⱕ0.44 ⫾ 1.04 for LT and ⱕ1.03 ⫾ 1.6 for P. There were no and 10 mL of blood was collected via direct jugular venous puncture. significant differences between groups within each trial. Lambs were then surgically castrated and tail-docked. Four lambs also underwent mulesing by an accredited practitioner using the industry After surgical castration. There was a significant elevation in the standard technique. All wounds

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ing by an accredited practitioner using the industry After surgical castration. There was a significant elevation in the standard technique. All wounds were treated with Tri-Solfen accord- response to P stimulation of the wound over time (P < 0.0001), with a ing to label recommendations or as outlined earlier. The lambs were significant treatment effect (P < 0.0001). Primary hyperalgesia devel- then transferred to holding pens and blood samples were collected by oped within 1 min of castration in the untreated and placebo-treated repeat jugular venous puncture at 30, 90 and 120 min following the lambs, but not in the Tri-Solfen-treated lambs. Response scores in the procedure, after which they were returned to their dams at pasture. Tri-Solfen-treated lambs were significantly below those of the untreated and placebo-treated lambs at all time points post procedure The blood samples were centrifuged, the plasma was frozen and then (P ⱕ 0.002) (Figure 1). Response to P stimulation of the skin sur- transferred to Agrisearch Analytical® (Rozelle, NSW) for analysis. rounding the castration wound did not change over time in the group Lignocaine and bupivacaine levels were determined using reverse- as a whole. Response scores were significantly lower in the Tri-Solfen- phase high-performance liquid chromatography with tandem mass treated lambs than in untreated and placebo-treated lambs at 1 min (P spectrometric detection. = 0.005) and 4 h (P = 0.02) (Figure 2). © 2010 University of Sydney Australian Veterinary Journal Volume 88, No 3, March 2010 69 PRODUCTION ANIMALS PRODUCTION ANIMALS Figure 1. Mean pain (P) response scores of lambs following stimulation of Figure 3. Mean response to light touch (LT) stimulation of the castration the surgical castration wound

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ponse scores of lambs following stimulation of Figure 3. Mean response to light touch (LT) stimulation of the castration the surgical castration wound comparing untreated, placebo only and wound comparing untreated, placebo only and topical anaesthesia topical anaesthesia treatments. treatments. Figure 2. Mean response to pain (P) stimulation of the skin surrounding Figure 4. Response to light touch (LT) stimulation of the skin surrounding the castration wound comparing untreated, placebo only and topical the castration wound. anaesthesia treatments. Response to LT stimulation of the castration wound. There was Surgically tail-docked lambs. There was evidence of primary hype- no significant overall change in the response to LT over time. ralgesia, with a significant elevation in response to P stimulation However, there was a significant treatment effect (P = 0.008), with LT between 1 min and 2 h (P < 0.0001). There was a significant treatment responses of the Tri-Solfen-treated lambs significantly less than those effect (P = 0.034): Tri-Solfen-treated lambs had P response scores that of the untreated lambs at 1 min (P = 0.003) and 2 h (P = 0.05). Placebo- were less than those of the untreated lambs at all time points (P = treated lambs were not significantly different to untreated lambs 0.008 at 4 h). The P response scores for the placebo-treated and (Figure 3). There appeared to be a mild decrease in the response to LT untreated lambs were not significantly different (Figure 5). There was stimulation of the skin surrounding the castration wound between no significant change over time to P stimulation around the wound. before treatment and 1 min after in both untreated and Tri-Solfen- However, there was a significant treatment effect (P = 0.018), with

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around the wound. before treatment and 1 min after in both untreated and Tri-Solfen- However, there was a significant treatment effect (P = 0.018), with treated lambs, but not in placebo-treated lambs, and there was a mild Tri-Solfen-treated lambs displaying response scores below those of increase in the response to LT stimulation of the skin surrounding the untreated lambs at all time points, which was statistically significant at castration wound between 1 min and 2 h afters in the untreated, but 4 h (P = 0.005) (Figure 6). not in the placebo- or Tri-Solfen-treated, lambs (P = 0.001) (Figure 4). HI tail-docked lambs. There was no evidence of primary hyperal- Direct sensory testing of the tail-docking wound and surrounding gesia and no significant treatment effect. However, the P response skin scores were significantly lower at the 4-h time point in the treated There was a significant change in the response to P over time (P < lambs compared with the untreated (P = 0.03) and placebo-treated 0.0001), with significant treatment effect. Lambs docked with a HI had lambs (P = 0.008) (Figure 5). There was evidence of early secondary response scores significantly below those of the surgically docked hyperalgesia, with a mild but significant change over time in response lambs (P < 0.0001). to P stimulation around the wound (P = 0.02), within 1 min of HI 70 Australian Veterinary Journal Volume 88, No 3, March 2010 © 2010 University of Sydney PRODUCTION ANIMALS PRODUCTION ANIMALS Figure 5. Mean response to pain (P) stimulation of the tail wound over Figure 7. Mean response to light touch (LT) stimulation of the tail wound time comparing 6 different treatment groups of lambs. over time comparing 6 different treatment groups of lambs. Figure 6. Mean response to pain

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l wound time comparing 6 different treatment groups of lambs. over time comparing 6 different treatment groups of lambs. Figure 6. Mean response to pain (P) stimulation around the tail wound Figure 8. Mean response to light touch (LT) stimulation of the skin sur- over time comparing 6 different treatment groups of lambs. rounding the tail wound over time comparing 6 different treatment groups of lambs. docking and most prominent in the untreated and placebo-treated (P < 0.001) and were not significantly different from the handled lambs (Figure 6). controls (Figure 9). Response to LT stimulation of the tail-docking wound. There was Plasma lignocaine and bupivacaine analyses a significant increase in LT response scores over time (P = 0.01) with Mean plasma lignocaine levels were 0.17 (⫾0.09), 0.12 (⫾0.06) and a significant treatment effect (P = 0.009). The greatest increase in 0.1 (⫾0.06)mg/L at 30, 90 and 120 min post treatment, respectively. response occurred between the 2- and 4-h time points in surgically The maximum recorded level at any time point in any of the lambs docked, untreated lambs (P = 0.01), which was not apparent in surgi- was 0.39 mg/L at 30 min post treatment. cally docked Tri-Solfen-treated lambs or those that were docked with a HI. Placebo-treated surgically docked lambs displayed intermediate Mean plasma bupivacaine levels were below the level of detection values (Figure 7). There was minimal response to LT stimulation of (<0.0025 mg/L) or quantification (<0.01 mg/L) in 5 lambs, with a skin surrounding the wound in all treatment groups (Figure 8). mean value ⫾SD of 0.014 ⫾ 0.003 mg/L in the remaining lambs at 30 min after treatment. Thereafter, bupivacaine levels at 90 and Pain-related behaviour 120 min were either at or below

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mg/L in the remaining lambs at 30 min after treatment. Thereafter, bupivacaine levels at 90 and Pain-related behaviour 120 min were either at or below the level of quantification in 10 lambs, There was a significant change in lamb behaviours over time (P < with 0.013 ⫾ 0.003 mg/L in the remaining animals. 0.001), with lambs exhibiting the greatest abnormalities in posture, gait or behaviour within the first 4 h after marking. Treatment type was Discussion shown to be highly significant (P < 0.001), with ring-castrated lambs displaying significantly higher pain-related behaviour scores than the There are rapidly emerging commercial and ethical imperatives to lambs in the surgical knife and HI treatment groups. Lambs treated find practical methods of alleviating the pain and stress inflicted on with topical anaesthesia displayed significantly less pain-related behav- farm animals during routine husbandry procedures such as castration iours than the untreated, ring-castrated and placebo-treated lambs and tail docking. Our study presents evidence that alleviation of pain © 2010 University of Sydney Australian Veterinary Journal Volume 88, No 3, March 2010 71 PRODUCTION ANIMALS PRODUCTION ANIMALS Figure 9. Mean scores for pain-related behav- iour of 6 different treatment groups of lambs compared with control lambs, using a numeri- cal rating scale. up to 4 h is achieved for lambs undergoing surgical castration plus Our studies of topical anaesthesia for livestock husbandry have used surgical or HI tail docking using a farmer-applied, spray-on topical Tri-Solfen because the lignocaine, bupivacaine and adrenalin in the anaesthetic formulation. This finding has major welfare implications delivered doses have proven effective for anaesthesia and haemostasis for

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in in the anaesthetic formulation. This finding has major welfare implications delivered doses have proven effective for anaesthesia and haemostasis for all livestock undergoing such procedures. of open wounds in human patients,19–24 and because it contains a viscous gel base that can be sprayed onto and adheres to open wounds. Local anaesthetic agents, such as lignocaine, when injected are highly Previous studies have demonstrated that topical anaesthesia is highly effective in alleviating the pain associated with castration and tail effective in alleviating the pain and improving the healing of mulesing docking,2,12–14 and the safety and efficacy profiles of local anaesthetic wounds in sheep, with lower acute cortisol responses and reduced agents are well described in sheep.15–18 Despite this, local anaesthetic wound pain and pain-related behaviour for up to and including 8 h injections are rarely used during routine husbandry procedures afterward.9,28 Our current results extend these findings by document- because of the practical and economic constraints. Topical anaesthe- ing that topical anaesthesia is also highly effective in alleviating the pain sia, applied during and/or immediately after the procedure, offers a associated with surgical castration plus surgical or HI tail docking. practical alternative that may still be highly effective for surgical pro- cedures. It can be difficult to quantify pain in animals and most authors use a combination of techniques. We elected to use behavioural analysis Local anaesthetic agents act directly on nerve tissue to elicit a revers- together with direct sensory testing. Quantitative sensory testing is a ible block of the conduction of signals responsible for the sensation of widely used, validated

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ect sensory testing. Quantitative sensory testing is a ible block of the conduction of signals responsible for the sensation of widely used, validated technique,29–32 which we have previously used pain. When applied to open wounds they can effect rapid and pro- in lambs to record the onset, evolution and distribution of pain from found local anaesthesia.9,19–24 They can also prevent or reduce the mulesing wounds and their response to a topical local anaesthetic.9 subsequent pain escalation response.25–27 Although it may seem coun- Our current findings of alleviation of wound pain and prevention of terintuitive to apply local anaesthetic after a procedure, there are sig- primary and secondary hyperalgesia in the first minute and up to 4 h nificant advantages to this approach in the sheep farm setting. Firstly, after surgical castration in Tri-Solfen-treated lambs is supported by for economic reasons, on-farm surgical procedures are performed finding that pain-related behaviour was also significantly reduced in very quickly, taking a matter of seconds; the pain involved may well be the Tri-Solfen-treated lambs. less than that of a local anaesthetic injection, particularly if a well- We found little evidence of direct wound pain after HI tail docking, as sharpened blade is used for the procedure. Secondly, by not having to identified in previous studies.6,10,11 The HI is believed to cauterise and wait for the anaesthetic agent to take effect before performing the destroy the nervous sensory tissue in the tail, resulting in a subsequent procedure, double-handling of the lamb is avoided and it is promptly loss of sensation.6,33,34 Mild and transient secondary hyperalgesia returned to its dam, minimising the stress of handling and separation. developed in the

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of sensation.6,33,34 Mild and transient secondary hyperalgesia returned to its dam, minimising the stress of handling and separation. developed in the surrounding tissues, but was prevented by treatment Thirdly, the agents can be applied by the farmer, without direct vet- with Tri-Solfen. We did not find any evidence of delayed wound erinary intervention. Further, postoperative pain may be more effec- healing in the HI docked lambs, with or without treatment. tively addressed as the actives are delivered directly to the traumatised nerve fibres and tissues that are the source of pain, and can be deliv- Surgical tail docking resulted in less immediate secondary hyperalge- ered in formulations designed for maximal adhesion and duration of sia. However, there was escalating primary allodynia and primary and effect. Finally, the anaesthetic agents can also be delivered in combi- secondary hyperalgesia over the ensuing 4 h, consistent with the pain nations with other agents, such as vasoconstrictors and antiseptics, escalation phenomenon. A significant, but incomplete, analgesic effect with possible synergistic and adjunctive wound care effects. was apparent with the use of Tri-Solfen and it was considered that 72 Australian Veterinary Journal Volume 88, No 3, March 2010 © 2010 University of Sydney PRODUCTION ANIMALS arterial bleeding from the tail may have diluted the anaesthetic agent lambs in Australia. However, the use of topical anaesthetic formula- and prevented it from adhering effectively to the cut skin edges of the tions has the potential to provide a practical and economic means of PRODUCTION ANIMALS tail wound. Nevertheless, the use of analgesia was still associated with reducing the pain associated with castration and tail docking and a significant

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ail wound. Nevertheless, the use of analgesia was still associated with reducing the pain associated with castration and tail docking and a significant reduction in pain-related behaviour. improve the welfare of millions of young lambs annually, both in Australia and internationally. Investigations as to whether it is simi- Blood plasma lignocaine and bupivacaine levels were well below the larly effective in cattle and pigs have commenced. toxic threshold of 6 mg/L (humans) and the toxic convulsive plasma level of 40 mg/L in sheep. Wound healing was unimpaired and we conclude that application of Tri-Solfen at the recommended rate to Acknowledgments lamb marking wounds will not be detrimental to their health. S Lomax was supported by a Jean Walker Fellowship Fund Faculty of Rubber ring castration and tail docking is widely used because of its Veterinary Science scholarship, and H Dickson by the Australian Wool ease and practicality. It is less amenable to pain alleviation with topical Education Trust. We are grateful for statistical advice from Drs P anaesthesia because of the poor skin penetrability of local anaesthetic Thomson and N Dhand from the University of Sydney and logistical agents. We included a rubber ring treatment group for behavioural support from Mr C Olsson and staff at ‘Royal Oak’, Goulburn, NSW comparison, as many consider this to be the most humane method of and Mr L Macsmith and family at ‘Corroboree’, Cudal, NSW. castration and docking. However, that opinion is not supported by our results. Lambs undergoing ring castration and docking in our trials References exhibited agitation, bleating, lateral and ventral recumbency, lip curling, kneeling, knee walking, writhing and other abnormal postures 1. Australian Bureau of Statistics. 7111.0:

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lateral and ventral recumbency, lip curling, kneeling, knee walking, writhing and other abnormal postures 1. Australian Bureau of Statistics. 7111.0: Principal Agricultural Commodities, Aus- indicative of ‘intense pain’ and ‘marked distress’. These behaviours tralia, Preliminary, 2007–09; http://www.abs.gov.au/AUSSTATS/abs@.nsf/ persisted beyond 2 h after application of the rings and is consistent Latestproducts/7111.0Main%20Features42008-09?opendocument&tabname= Summary&prodno=7111.0&issue=2008-09&num=&view=. Retrieved December with previous reports.3,13 The nature of their distress ‘dominated their 2009 experience’35 and rendered them oblivious to external environmental 2. Dinniss AS, Mellor DJ, Stafford KJ et al. Acute cortisol responses of lambs to stimulation, to the extent that they were unsuitable for direct wound castration using a rubber ring and/or a castration clamp with or without local anaesthetic. NZ Vet J 1997;45:114–121. sensory testing. Our results concur with Grant,6 who determined a 3. Mellor DJ, Murray L. Effects of tail docking and castration on behaviour and hierarchy of pain associated with different marking methods, with plasma cortisol concentrations in young lambs. Res Vet Sci 1989;46:387–391. rubber ring castration and tail docking being the most painful (and ear 4. Thornton PD, Waterman-Pearson AE. Quantification of the pain and distress tagging as the least most painful intervention), and noted that ‘All responses to castration in young lambs. Res Vet Sci 1999;66:107–118. 5. Rhodes RC, Nippo MM, Gross WA. Stress in lambs (Ovis aries) during a routine treatments involving the use of tight rubber rings resulted in signifi- management procedure: evaluation of acute and chronic responses. Comp cant abnormal posture

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nvolving the use of tight rubber rings resulted in signifi- management procedure: evaluation of acute and chronic responses. Comp cant abnormal posture and active pain behaviour displays.’ Biochem Physiol 1994;107A:181–185. 6. Grant C. Behavioural responses of lambs to common painful husbandry pro- Arguments that rubber rings cause less pain and stress are generally cedures. Appl Anim Behav Sci 2004;87:255–273. based on interpretation of biochemical measurements, with greater 7. Fell LR, Shutt DA. Behavioural and hormonal responses to acute surgical stress in sheep. Appl Anim Behav Sci 1989;22:283–294. elevation and persistence of the cortisol response following surgical 8. Farm Animal Welfare. Report on the implications of castration and docking for procedures. However, is it appropriate to compare surgical and non- the welfare of lambs. Crown copyright May 2008. http://www.fawc.org.uk/pdf/ surgical procedures using the cortisol response as a measure of pain? report-080630.pdf. Accessed September 2009. Surgical wounding (breaching the skin) prompts a unique physiologi- 9. Lomax S, Sheil M, Windsor PA. Impact of topical anaesthesia on pain alleviation and wound healing in lambs after mulesing. Aust Vet J 2008;86:159–168. cal response that is designed to maintain blood volume and institute 10. Graham MJ, Kent JE, Molony V. Effects of four analgesic treatments on the body defences and wound healing. Cortisol secretion is an important behavioural and cortisol responses of 3-week-old lambs to tail docking. Vet J part of this physiological response,36 which occurs even in the complete 1997;153:87–97. absence of pain, such as when patients are unconscious and/or under 11. Lester SJ, Mellor DJ, Holmes RJ et al. Behavioural and cortisol responses of lambs to

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of pain, such as when patients are unconscious and/or under 11. Lester SJ, Mellor DJ, Holmes RJ et al. Behavioural and cortisol responses of lambs to castration and tailing using different methods. NZ Vet J 1996;44:45–54. full general anaesthesia.37–40 A more protracted cortisol response fol- 12. Wood GN, Molony V, Fleetwood-Walker SM et al. Effects of local anesthesia lowing surgical castration does not necessarily indicate greater or more and intravenous naloxone on the changes in behaviour and plasma concentra- protracted pain compared with rubber ring castration. It may simply tions of cortisol produced by castration and tail docking with tight rubber rings in young lambs. Res Vet Sci 1991;51:193–199. indicate that there has been a greater breach of the skin. 13. Dinniss AS, Stafford KJ, Mellor DJ et al. The behaviour pattern of lambs after castration using a rubber ring and/or castrating clamp with or without local Our results indicate that castration and tail docking in lambs can be anaesthetic. NZ Vet J 1999;47:198–203. achieved with minimal pain and distress using surgical castration, HI 14. Mellor DJ, Stafford KJ. Acute castration and/or tailing distress and its allevia- tail docking and intra-/postoperatively applied topical anaesthetic. tion in lambs. NZ Vet J 2000;48:33–43. This technique offers the sheep industry a welfare-appropriate alter- 15. Morishima HO, Pedersen H, Finster M et al. Toxicity of lidocaine in adult, newborn, and fetal sheep. Anesthesiology 1981;55:57–61. native to both the currently used methods: surgery without analgesia 16. Rutten A, Nancarrow C, Mather L et al. Hemodynamic and central nervous and rubber rings. In our opinion, investigations of other methods of system effects of intravenous bolus doses of lidocaine,

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ynamic and central nervous and rubber rings. In our opinion, investigations of other methods of system effects of intravenous bolus doses of lidocaine, bupivacaine, and ropiv- analgesia are required to address the considerable welfare concerns acaine in sheep. Anesth Analg 1989;69:291–299. 17. Feldman H, Dvoskin S, Halldin M et al. Comparative local anesthetic efficacy that occur with the routine use of rubber rings for castration only or and pharmacokinetics of epidurally administered ropivacaine and bupivacaine in for combined castration and tail docking. the sheep. Region Anesth 1997;22:451–460. 18. Huang Y, Pryor M, Mather L et al. Cardiovascular and central nervous system Tri-Solfen is currently only available under a restricted use permit effects of intravenous levobupivacaine and bupivacaine in sheep. Anesth Analg through veterinarians for use in alleviating post-mulesing pain in 1998;86:797–804. © 2010 University of Sydney Australian Veterinary Journal Volume 88, No 3, March 2010 73 PRODUCTION ANIMALS 19. Brofeldt B, Cornwell P, Doherty D et al. Topical lidocaine in the treatment of 30. Hardie EM. Recognition of pain behaviour in animals In: Hellebrekers L, editor. partial-thickness burns. J Burn Care Rehabil 1989;10:63–68. Animal pain. Van der wees, Utrecht, The Netherlands, 2000;51–69. 20. Jellish WS, Gamelli RL, Furry PA et al. Effect of topical local anesthetic appli- 31. Kawamata M, Takahashi T, Kozuka Y et al. Experimental incision-induced pain PRODUCTION ANIMALS cation to skin harvest sites for pain management in burn patients undergoing in human skin: effects of systemic lidocaine on flare formation and hyperalgesia. skin-grafting procedures. Ann Surg 1999;229:115–120. Pain 2002;100:77–89. 21. Kokinsky E, Cassuto J, Sinclair R et al.

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are formation and hyperalgesia. skin-grafting procedures. Ann Surg 1999;229:115–120. Pain 2002;100:77–89. 21. Kokinsky E, Cassuto J, Sinclair R et al. Topical wound anaesthesia in children: a 32. Duarte A, Pospisilova E, Reilly E et al. Reduction of postincisional allodynia by temporary postoperative pain relief. Acta Anaesthiol Scand 1999;43:225–229. subcutaneous bupivacaine: findings with a new model in the hairy skin of the rat. 22. Sinclair R, Cassuto J, Hogstrom S. Topical Anaesthesia with lidocaine aerosol in Anaesthesiology 2005;103:113–125. the control of postoperative pain. Anaesthesiology 1988;68:895–901. 33. Groer MW, Shekleton ME. Basic pathophysiology: A conceptual approach. 23. Smith GA, Strausbaugh SD, Harbeck-Weber C et al. Comparison of topical Mosby, St Louis, 1983;643. anesthetics without cocaine to tetracaine-adrenaline-cocaine and lidocaine infil- 34. Johnston D. Burns: electrial, chemical and cold injuries. In: Slatter DH, tration during repair of lacerations: bupivacaine-norepinephrine is an effective editor. Textbook of small animal surgery. WB Saunders, Philadelphia, 1985;516– new topical anesthetic agent. Pediatrics 1996;97:301–307. 533. 24. Stewart A, Simpson P, Rosenberg N. Use of topical lidocaine in pediatric 35. Wood G, Molony V. Welfare aspects of castration and tail docking of lambs. In laceration repair: A review of topical anaesthetics. Pediatr Emerg Care 1998;14:419– Pract 1992;14:2–7. 423. 36. Grose R, Werner S, Kessler D et al. A role for endogenous glucocorticoids in 25. Dahl JB, Brennum J, Arendt-Nielsen L et al. the effect of pre- versus post-injury wound repair. EMBO Rep 2002;3:575–582. infiltration with lidocaine on thermal and mechanical hyperalgesia after heat 37. Malatinsky J, Vigas M, Jurcovicova

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d repair. EMBO Rep 2002;3:575–582. infiltration with lidocaine on thermal and mechanical hyperalgesia after heat 37. Malatinsky J, Vigas M, Jurcovicova J, Jezova D, Garayova S, Minarikova M. The injury to the skin. Pain 1993;53:43–51. patterns of endocrine response to surgical stress during different types of anes- 26. Lam KW, Pun TC, Ng EH et al. Efficacy of preemptive analgesia for wound pain thesia and surgery in man. Acta Anaesthesiol Belg 1986;37:23–32. after laproscopic operations in infertile women: a randomised, double blind and 38. Fox SM, Mellor DJ, Firth EC et al. Changes in plasma cortisol concentrations placebo control study. Br J Obstet Gynaecol 2004;111:340–344. before, during and after analgesia, anaesthesia and anaesthesia plus ovariohys- 27. Pogatzki EM, Vandermeulen EP, Brennan TJ. Effect of plantar local anaesthetic terectomy in bitches. Res Vet Sci 1994;57:110–118. injection on dorsal horn neuron activity and pain behaviours caused by incision. 39. Hughan SC, Loose JM, Caddy DJ et al. Combined xylazine and ketamine as an Pain 2002;97:151–161. analgesic regimen in sheep. Aust Vet J 2001;79:207–211. 28. Paull DR, Lee C, Colditz IG et al. The effect of topical anaesthetic formulation, 40. Baldini G, Bagry H, Carli F. Depth of anesthesia with desflurane does not systemic flunixin and carprofen, singly or in combination, on cortisol and behav- influence the endocrine-metabolic response to pelvic surgery. Acta Anaesthesiol ioural responses of Merino lambs to mulesing. Aust Vet J 2007;85:98–106. Scand 2008;52:99–105. 29. Rolke R, Magerl W, Campbell KA et al. Quantitative sensory testing: a compre- hensive protocol for clinical trials. Eur J Pain 2006;10:77–88. (Accepted for publication 5 August 2009) BOOK REVIEW avj_551 74..81

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testing: a compre- hensive protocol for clinical trials. Eur J Pain 2006;10:77–88. (Accepted for publication 5 August 2009) BOOK REVIEW avj_551 74..81 Where to see birds in Victoria. Edited by Tim Dolby, Penny Johns and Sally Symonds. Published for Birds Australia by Jacana Books, Allen and Unwin, NSW, Australia, 2009. 192 pages. AUD$35.00. ISBN 978 1 74175 736 1. T he book is published to assist people find the special birds of The book also contains an annotated list of bird species and where Victoria which from the photographs mean visiting very the less common species will be likely observed in the wild. A com- beautiful places across Victoria. Victoria is divided into 8 prehensive index provides for easy searching. regions making it easier to identify one of the 43 places to go and Pictures of the general habitat and some birds likely to be seen at see interesting native birds near you are located. Places, as close as each location are included and are of excellent quality. The book is 4 km to the Melbourne GPO, are reliable sites for seeing a wide of a size suitable for hand carriage while bird spotting and keeping variety of birds in habitat ranging from forests, wetlands, open in the glove box of the car ready for another twitching session. woodlands to grasslands. The book outlines the best season in which to see the birds at each of the 43 locations. Andrew Turner Being a Birds Australia publication, the book is supported by regular Princes Hill Victoria. surveys of bird populations recorded by enthusiast members making the likelihood of seeing the described species highly likely. doi: 10.1111/j.1751-0813.2010.00551.x © 2010 The Authors 74 Australian Veterinary Journal Volume 88, No 3, March 2010 Journal compilation © 2010 Australian Veterinary

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751-0813.2010.00551.x © 2010 The Authors 74 Australian Veterinary Journal Volume 88, No 3, March 2010 Journal compilation © 2010 Australian Veterinary Association