Influence of local anaesthesia on pain and distress induced by two bloodless castration methods in young lambs

To assess short- and long-term effects of bloodless castration methods with and without local anaesthesia, behavioural and cortisol responses of lambs were used as indicators of pain and distress. Seventy lambs, aged 2-7 days, were control-handled or castrated by Burdizzo or rubber ring methods with and without local anaesthesia. Either 5 mL of diluted lidocaine (4 mg/kg) or physiological sodium chloride solution was distributed in both spermatic cords and the scrotal neck. The serum cortisol response was monitored for 48 h, and behavioural and clinical traits were followed for three months. Local anaesthesia tended to reduce behavioural and cortisol responses after Burdizzo castration and provided a significant reduction after rubber ring castration. Prolonged pain after rubber ring castration with anaesthesia was not evident. If combined with local anaesthesia, both the rubber ring and the Burdizzo methods are acceptable methods for castration of lambs up to one week of age.     

Influence of local anaesthesia on short- and long-term pain induced in calves by three bloodless castration methods

Behavioural and cortisol responses of calves were used as indicators of pain to assess short- and long-term effects of three bloodless castration methods with and without local anaesthesia. Eighty calves, aged 21 to 28 days, were control handled (20) or castrated by Burdizzo (25), rubber ring (25), or crushing technique (10). Either a total volume of 10 ml of Lidocaine or NaCl was distributed in both spermatic cords and the scrotal neck. The plasma cortisol response was monitored for 72 hours, and behavioural and clinical traits over a three-month period. Castration success was assessed by degree of atrophy and histological tissue examination. The crushing technique cannot be recommended due to incomplete castration success, and the evaluation was stopped after 10 animals. Local anaesthesia reduced the level of indicators of acute pain after Burdizzo and rubber ring technique. It did, however, not result in a totally painless castration. When castration is performed at the age of 3 to 4 weeks, the rubber ring but not the Burdizzo method showed evidence of chronic pain lasting for several weeks.     

Effect of local anaesthesia on short- and long-term pain induced by two bloodless castration methods in calves

Behavioural and cortisol responses of calves were used as indicators of pain to assess short- and long-term effects of bloodless castration methods with and without local anaesthesia. Seventy calves, aged 21-28 days, were control handled (20) or castrated using the Burdizzo (25) or rubber ring technique (25). Either 10 mL lidocaine or NaCl were distributed in both spermatic cords and the scrotal neck. The plasma cortisol response was recorded for 72 h, and behavioural and clinical traits monitored over a three month period. Local anaesthesia reduced the level of indicators of acute pain after both the Burdizzo and rubber ring techniques. It did not, however, result in a totally painless castration. As there was evidence of chronic pain lasting for several weeks after rubber ring castration, the Burdizzo method is judged to be preferable to the rubber ring technique.     

Quantification of the pain and distress responses to castration in young lambs

Pain and distress following castration were assessed in lambs using three indicators: behaviour, plasma cortisol and mechanical nociceptive thresholds. Three castration methods: rubber ring (RR), combined ring and Burdizzo clamp (CM) and surgery (SU) were compared. The effects of castration following local anaesthetic pre-treatment (LA) and castration performed under general anaesthetic (GA) were compared to castration performed with no anaesthetic. This gave a 4 x 3 x 3 block design i.e. 36 experimental treatments. Six lambs were allocated to each treatment i.e. 216 lambs were used in all. SU produced the greatest response, followed by RR then CM castration. LA abolished the responses to RR and CM castration but had no effect on the response to SU castration. GA did not reduce the responses to RR and SU but abolished the rise in mechanical nociceptive thresholds and markedly attenuated active pain behaviours in lambs CM castrated without anaesthesia. This suggests that the clamping procedure itself rather than post-castration pain and distress is responsible for the rise in nociceptive thresholds and active pain behaviours in CM castrated lambs.     

Effect of local anaesthesia and/or analgesia on pain responses induced by piglet castration

Background

Surgical castration in male piglets is painful and methods that reduce this pain are requested. This study evaluated the effect of local anaesthesia and analgesia on vocal, physiological and behavioural responses during and after castration. A second purpose was to evaluate if herdsmen can effectively administer anaesthesia.

Methods

Four male piglets in each of 141 litters in five herds were randomly assigned to one of four treatments: castration without local anaesthesia or analgesia (C, controls), analgesia (M, meloxicam), local anaesthesia (L, lidocaine), or both local anaesthesia and analgesia (LM). Lidocaine (L, LM) was injected at least three minutes before castration and meloxicam (M, LM) was injected after castration. During castration, vocalisation was measured and resistance movements judged. Behaviour observations were carried out on the castration day and the following day. The day after castration, castration wounds were ranked, ear and skin temperature was measured, and blood samples were collected for analysis of acute phase protein Serum Amyloid A concentration (SAA). Piglets were weighed on the castration day and at three weeks of age. Sickness treatments and mortality were recorded until three weeks of age.

Results

Piglets castrated with lidocaine produced calls with lower intensity (p < 0.001) and less resistance movements (p < 0.001) during castration. Piglets that were given meloxicam displayed less pain-related behaviour (huddled up, spasms, rump-scratching, stiffness and prostrated) on both the castration day (p = 0.06, n.s.) and the following day (p = 0.02). Controls had less swollen wounds compared to piglets assigned to treatments M, L and LM (p < 0.001). The proportion of piglets with high SAA concentration (over threshold values 200, 400 mg/l) was higher (p = 0.005; p = 0.05) for C + L compared to M + LM. Ear temperature was higher (p < 0.01) for controls compared to L and LM. There were no significant treatment effects for skin temperature, weight gain, sickness treatments or mortality.

Conclusions

The study concludes that lidocaine reduced pain during castration and that meloxicam reduced pain after castration. The study also concludes that the herdsmen were able to administer local anaesthesia effectively.     

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

Objective To investigate the effect of a topical anaesthetic formulation on pain alleviation, wound healing and systemic levels of local anaesthetic actives in lambs undergoing castration and tail docking. Design Three placebo-controlled and/or randomised experiments were conducted using three groups of Merino lambs (n = 62, 68 and 19) undergoing routine castration and tail docking. Procedure Surgical castration, with either surgical or hot-iron tail docking, was performed with and without the application of topical anaesthetic (Tri-Solfen®) or placebo. The effects of this procedure were compared with those of rubber ring castration and tail docking, and of the handled but unmarked controls. Wound pain was assessed using calibrated Von-Frey monofilaments over a 4-h period, pain-related behaviour was assessed over 5 h, wound healing was assessed at 14 and 28 days, and the plasma levels of lignocaine and bupivacaine were determined. Results Rapid and up to 4 h primary hyperalgesia developed following surgical castration and tail docking in the untreated and placebo-treated lambs. It was absent in the castration wounds, and significantly reduced in the tail-docking wounds, of the treated lambs. Hot-iron docking was associated with mild and transient secondary hyperalgesia, which was abolished by the topical anaesthesia. There was a significant reduction in pain-related behaviours in treated lambs, which were not significantly different in their behaviour to the sham-operation handled controls. Plasma lignocaine and bupivacaine levels were below the toxic thresholds in all tested lambs. Conclusion Topical anaesthesia alleviates wound pain and significantly reduces pain-related behaviours in lambs undergoing surgical castration plus surgical or hot-iron tail docking, without a negative effect on wound healing or a risk of systemic toxicity.     

Reduction in pain suffered by lambs at castration

The acute pain produced by bloodless castrators was studied by comparing the behavioural and plasma cortisol changes in groups (n=8) of 3-week-old Dorset cross lambs after castration with a 22 cm (9") Burdizzo, a new power assisted castrator and by a combined method using a Burdizzo and elastrator ring. The time spent in abnormal postures (52-58 min) and the peak cortisol response (110-120 mmol l(-1)) were similar for the three methods, although the powered castrator produced a more sustained response. The Burdizzo method halved the incidence of active behaviours compared with the powered castrator and combined methods (16 versus 30, 32 counts). Intratesticular local anaesthetic administered 2 min before the Burdizzo castrator and combined method, or intramuscular injection of the non-steroidal anti-inflammatory drug diclofenac, 20 min before the application of a Burdizzo, significantly reduced the peak plasma cortisol response to 80 nmol l(-1). Diclofenac also significantly reduced the time spent trembling or in abnormal postures.     

Cortisol responses of young lambs to castration and tailing using different methods

Lambs at 4-5 weeks of age were studied during the first 4 hours after castration and/or tailing using three methods in various commonly used combinations. The methods were cutting with a knife, application of constricting rubber rings and using a heated docking iron (tailing only). The integrated cortisol response (area under the cortisol curve) was determined for each lamb during the first 4 hours after treatment and was considered to reflect the overall magnitude of the lamb's acute distress response. On that basis, cut lambs (tailing only, castration only, castration plus tailing) experienced more distress than any other groups. Also the distress response (indicated by elevated plasma cortisol concentrations) lasted longer than 4 hours in cut lambs, unlike all other groups. The use of rings apparently caused similar distress when lambs were castrated only, were castrated plus tailed, or were short-scrotumed (testes pressed against the abdominal wall by a distally located scrotal ring) plus tailed. The magnitudes of distress apparently caused by tailing alone with a ring or a docking iron were similar and were lower than the distress caused by any other castration and/or tailing procedure. It is concluded that acute distress responses to these husbandry procedures would be minimised in lambs of this age if rings and/or a docking iron were used in preference to a knife.     

Acute castration and/or tailing distress and its alleviation in lambs

PURPOSES AND APPROACH: Acute castration and/or tailing distress in lambs has been examined extensively during the last decade. At least 59 different approaches to assessing and alleviating this distress have been reported so that the literature is quite complex. The purpose of this paper is to provide an overview of the literature on castration and/or tailing distress, where the distress was assessed using acute changes in plasma cortisol concentrations. A method of analysis involving the integrated cortisol response (i.e. the areas under the cortisol curves while the plasma concentration is above pretreatment values) to each treatment and using treatments which were common to different studies as reference points, allowed meaningful comparison within and between studies. A 6-point ranking scale emerged, where rank 1 represented the least distress and rank 6 the most distress. COMPARISON OF ACUTE DISTRESS RESPONSES: This analysis revealed the following major points. Surgical methods of castration and/or tailing cause the greatest cortisol responses (rank 5 or 6). Most ring and ring plus clamp methods of castration plus tailing or castration, used without a local anaesthetic or systemic analgesic, cause rank 4 responses. One form of ring plus clamp castration (i.e. applying the clamp for 10 s across the full width of the scrotum distal to the ring in lambs aged no more than 1 week) reduces the cortisol response to rank 1. When these lambs are also tailed by applying a ring and clamp in a similar manner to the tail, they also exhibit a rank 1 response. Local anaesthetic given 10-20 or 12 min or 10-15 s before or immediately after ring only castration and/or tailing can virtually abolish the cortisol response (rank 1), depending on the site(s) of injection. For ring or ring plus clamp castration, the most effective sites (as judged by cortisol responses) are the neck of the scrotum or the testes. Delivery of local anaesthetic to achieve successful nerve blockade can be by needle, high-pressure needleless administration or, for the tail only, by an aerosol spray. Local anaesthetic injected into the scrotal neck, spermatic cords and/or testes has little effect on the overall cortisol response to clamp castration. Reductions in cortisol responses to clamp castration or to ring tailing can occur after administration of non-steroidal anti-inflammatory drugs. Most tailing methods elicit cortisol responses that are several ranks lower than those caused by castration plus tailing or castration alone. Although tailing by most methods elicits rank 1 cortisol responses, the use of local anaesthetic or non-steroidal anti-inflammatory drugs can reduce the response within the rank 1 range. RECOMMENDATION: Farmers should be encouraged to choose the lowest ranked method that is economically and practically feasible for them. Specific methods such as surgical castration should be discouraged.     

Effects of local anaesthesia or local anaesthesia plus a non-steroidal anti-inflammatory drug on the acute cortisol response of calves to five different methods of castration

The cortisol response of calves to different methods of castration (ring, band, surgical, clamp) with or without local anaesthetic, or local anaesthetic plus a non-steroidal anti-inflammatory drug were recorded. All methods of castration caused a significant cortisol response and by inference pain and distress. Band castration caused a greater cortisol response than ring castration but the responses were eliminated by local anaesthetic. The cortisol response to surgical castration, by traction on the spermatic cords or by cutting across them with an emasculator, was not diminished by local anaesthetic but when ketoprofen was given with local anaesthetic the cortisol response was eliminated. Local anaesthetic did reduce the behavioural response to cutting the scrotum and handling the testes. Clamp castration caused the smallest cortisol response which was reduced or eliminated by local anaesthetic or local anesthetic plus ketoprofen respectively, but this method of castration was not always successful.     

Effects of tail docking and castration on behaviour and plasma cortisol concentrations in young lambs

Behavioural and cortisol responses of lambs to the usual husbandry practices of castration and, or, tail docking using tight rubber rings were investigated between birth and seven days old. There were four treatments: control handling and blood sampling (n = 52), tail-docking (T) (n = 57), castration plus tail-docking (CT) (n = 54) and intravenous adrenocorticotrophin injection (ACTH) (n = 52). After treatment there was a transient rise in plasma cortisol concentration, the magnitude and duration of which increased in the following order; control, T, CT and ACTH. Behavioural characteristics indicative of distress included restlessness (standing up and lying down frequently, rolling, kicking, stamping), lateral recumbency, immobility with neck extension and hyperventilation. Using changes in cortisol concentrations and behaviour the lamb responses were characterised as reflecting 'mild disturbance without distress' (control, ACTH), 'mild distress' (T) and 'marked distress' (CT). The mild distress lasted for about 30 minutes in T lambs and marked distress for about 60 minutes in CT lambs.     

Impact of topical anaesthesia on pain alleviation and wound healing in lambs after mulesing

Objective     To investigate the impact of using the topical anaesthetic preparation Tri-Solfen® on pain alleviation and wound healing in lambs undergoing mulesing.
Design   Three separate trials, placebo controlled and/or randomised, were carried out over a 5 month period on three mobs of between 60 and 263 merino lambs undergoing routine mulesing.
Procedure     Wound pain was assessed using 10 and 75 g calibrated Von-Frey monofilaments to determine sensitivity to light touch and pain stimulation over a 4 to 8 h period. Pain-related behaviour was documented by trained, blinded observers using a numerical rating scale. Wound healing rates were determined using scaled digital photography and image analysis software to calculate contraction in wound surface area 2 and 4 weeks after mulesing.
Results     There was rapid (3 min) and prolonged (up to 8 h) wound analgesia as shown by pain response scores (P ≤ 0.01), with absent or significantly diminished primary and secondary hyperalgesia (P ≤ 0.01) and significant reduction in pain-related behaviour (P < 0.001) in treated versus untreated lambs. In addition there was improved wound healing in the treated lambs (P ≤ 0.05).
Conclusion     Tri-Solfen® effects rapid and prolonged wound analgesia, reduction in pain-related behaviour and improved wound healing in lambs undergoing routine mulesing, providing effective alleviation of pain associated with routine mulesing in sheep.     

Effects of castration on behaviour and plasma cortisol concentrations in young lambs, kids and calves.

Behavioural and cortisol responses to the husbandry practice of castration with tight rubber rings were investigated in lambs and kids one day after birth and in hand reared calves aged one to seven days. There were three treatments: control handling and blood sampling, castration and, in lambs and kids only, intravenous adrenocorticotrophin injection (ACTH). The integrated cortisol responses (area under the cortisol curve) in lambs and kids were least in control, intermediate in castrated and greatest in ACTH animals. No cortisol responses were detected in control or castrated calves. The incidences of behaviour used to assess the intensity of distress apparently experienced in the different species corresponded generally with the magnitudes of the cortisol responses. Behavioural and cortisol responses together suggested that the distress caused by castration was greatest in lambs, intermediate in kids and least but not necessarily absent in hand reared calves.     

Behavioural and cortisol responses of lambs to castration and tailing using different methods

Lambs at 4-5 weeks of age were studied during the first 4 hours after castration and/or tailing using three methods in various commonly used combinations. The methods were: cutting with a knife, application of constricting rubber rings and using a heated docking iron (tailing only). Behaviour was monitored by quantifying the incidences of restlessness (during the first hour only), normal and abnormal standing/walking, and normal and abnormal lying. Plasma cortisol concentrations were also measured in samples taken at intervals during the 4 hours after treatment. With the knife, abnormal standing/walking predominated throughout the fist 4 hours and beyond, and restlessness was virtually absent. Plasma cortisol concentrations in knife-treated lambs remained above pretreatment values for at least 4 hours. With rings, high restlessness was invariably present during the first 30-45 minutes, and much of the associated standing/walking and lying was abnormal, but all behaviours had returned to control values within 4 hours of treatment, as had the plasma cortisol concentrations. There were no correlations between the incidences of abnormal behaviours and the plasma cortisol concentrations during the first 4 hour after any treatment, except that when abnormal behaviour was present the cortisol concentrations were greater than pretreatment values, and vice versa. Thus, the presence/absence of the abnormal behaviours reported here allowed an assessment of the duration of distress after castration and/or tailing. However, as the behavioural responses to castration and/or tailing were broadly procedure-specific, so that the responses to the knife and rings were not apparently part of the one behavioural continuum, it is argued that the relative intensities of distress caused by the two procedures cannot be assessed from behaviour alone. Rather, reference must also be made to established physiological indices of distress such as plasma cortisol concentration. On that basis, the knife treatments apparently caused greater and more protracted distress responses than did the ring or docking iron treatments, and should therefore be avoided. However, ring-treated lambs, especially those castrated or castrated and tailed apparently experienced distress, so that more benign alternatives to the use of rings should also be sought.     

Effect of bupivacaine liposome suspension administered as a local anesthetic block on indicators of pain and distress during and after surgical castration in dairy calves

Castration is a routine procedure performed on beef and dairy operations in the United States. All methods of castration cause behavioral, physiologic, and neuroendocrine changes associated with pain. The American Veterinary Medical Association and the American Association of Bovine Practitioners recommend that anesthesia and analgesia be administered during castration. The objective of this study was to evaluate the effectiveness of bupivacaine liposome suspension, a novel, long-acting, local anesthetic formulation administered as a nerve block at castration. The authors chose to investigate this novel formulation as an alternative to the current industry standards using lidocaine nerve blocks alone or in combination with meloxicam. Thirty male Holstein calves, 16 to 20 wk of age, were enrolled and randomly assigned to one of the four treatment groups prior to surgical castration: 1) bupivacaine liposome suspension block + oral placebo (BUP), 2) lidocaine block + oral placebo (LID), 3) lidocaine block + oral meloxicam (1 mg/kg) (LID + MEL), and 4) saline block + oral placebo (CON). Biomarkers were collected at −24 h and from 0 to 120 h post-castration and included infrared thermography, pressure mat gait analysis, chute defense and behavior scoring (pain and activity), and blood sampling for serum cortisol and prostaglandin E₂ metabolites (PGEMs). Responses were analyzed using repeated measures, with calf nested in treatment as a random effect, and treatment, time, and their interaction designated as fixed effects. The results from pressure mat gait analysis show that the CON had a shorter front limb stance time from baseline (−8.73%; 95% confidence interval [CI]: −24.84% to 7.37%) compared with BUP and LID + MEL (>5.70%; 95% CI: −22.91% to 23.79%) (P < 0.03). The CON tended to have an increase in front limb force from baseline (6.31%; 95% CI: −1.79% to 14.41%) compared with BUP, LID, and LID + MEL (<−5.06%; 95% CI: −14.22% to 0.95%) (P < 0.04). The CON displayed higher counts of hunched standing (2.00; 95% CI: 1.68 to 2.32) compared with LID + MEL (1.43; 95% CI: 1.13 to 1.72) (P = 0.05). The CON had higher cortisol concentrations at 24 h (7.70 ng/mL; 95% CI: 1.52 to 13.87 ng/mL) relative to BUP (3.11 ng/mL; 95% CI: −2.56 to 8.79 ng/mL) (P = 0.002). At 4 and 24 h, LID + MEL had lower PGEM concentrations from baseline (−32.42% and −47.84%; 95% CI: −78.45% to −1.80%) compared with CON (27.86% and 47.63%; 95% CI: 7.49% to 82.98%) (P < 0.02). The administration of bupivacaine liposome suspension as a local anesthetic block at the time of castration was as effective at controlling pain as a multimodal approach of lidocaine and meloxicam.     

Effects of local anesthesia and intravenous naloxone on the changes in behaviour and plasma concentrations of cortisol produced by castration and tail docking with tight rubber rings in young lambs.

The reliability of some behavioral and physiological indices used for the recognition and assessment of acute pain in lambs after castration and tail docking has been examined. Changes in the indices were measured after blocking neural activity with local anaesthetic (lignocaine) and after an opioid antagonist (naloxone) was administered. Six lambs, aged less than one week, were allocated randomly to each of six treatments. (i) control handling and blood sampling; (ii) castration plus tail docking with tight rubber rings; (iii) local anaesthesia; (iv) local anaesthesia followed by castration and tail docking; (v) intravenous naloxone only (0.2 mg kg-1); and (vi) intravenous naloxone followed by castration and tail docking. Local anaesthesia eliminated the behavioural and plasma cortisol changes which usually follow castration and tail docking. Naloxone had a limited effect on the increase in cortisol but altered the behaviour. The results support the view that such indices are useful for assessment of the response to acute pain and that, although endogenous opioids do reduce pain in young lambs after castration and tail docking, the effect is small.     

The castration of male lambs by immunization against GnRH

The objective of this study was to evaluate the effect of a GnRH-vaccine in the ram lamb. Experiments were performed using 20 male lambs, randomly divided into a test (GnRH-immunization) and control group (physiological NaCl-solution). At a body weight of 20 kg (age 2-3 months) and three weeks later, all animals of the test group received 2 ml of Improvac (CSL Limited, Parkville, Victoria, Australia). The body weight as well as the blood testosterone concentration were measured weekly for 16 weeks. Thereafter, blood samples for testosterone analysis were taken monthly in immunized lams only. After the booster injection testicular growth was suppressed and plasma testosterone remained at low values < 0.1 ng/ml for at least 12 weeks. The mean corresponding testosterone concentrations for the control lambs ranged between 0.1 and 0.9 ng/ml plasma. An increase of testosterone was observed in 8 of 10 immunized animals between 3 to 7 months after the booster dose. The control lambs showed a tendency for better growth rate than vaccinated animals, but the difference was not significant. Our results demonstrate that in prepubertal ram lambs two immunizations with Improvac, three weeks apart, can suppress testosterone secretion and testicular growth at least for three months after the booster injection. For a suppression of reproductive function longer than three months after the second vaccination, a third immunization is needed at this time or when testicular growth is beginning.     

Effects of early human handling on the pain sensitivity of young lambs

Objective Pain sensitivity of lambs changes over the first weeks of life. However, the effects of early treatments such as human handling on pain sensitivity are unknown for this species. This study investigated the effects of regular early gentle human handling on the pain sensitivity of lambs, indicated by their behavioural responses to tail docking. Study design Prospective part‐blinded experimental study. Animals Twenty‐nine singleton Coopworth lambs (females n = 14, males n = 15). Methods Starting at one day of age, lambs were either handled twice daily for 2 weeks (Handled), were kept in the presence of lambs who were being handled but were not handled themselves (Presence), or were exposed to a human only during routine feeding and care (Control). At 3 weeks of age, all lambs were tail docked using rubber rings. Changes in behaviour due to docking were calculated and change data were analyzed using two‐way anova with treatment and test pen as main factors. Results All lambs showed significant increases in the frequency and duration of behaviours indicative of pain, including ‘abnormal’ behaviours, and decreases in the frequency and duration of ‘normal’ behaviours after docking. Handled lambs showed a smaller increase in the time spent lying abnormally after docking than did Control lambs (mean transformed change in proportion of 30 minutes spent ± SE: Control 0.55 ± 0.04; Handled 0.38 ± 0.03; Presence 0.48 ± 0.03; C versus H t = 3.45, p = 0.007). Conclusions and clinical relevance These results provide some evidence that handling early in life may reduce subsequent pain sensitivity in lambs. While the behavioural effects of handling on pain behaviour were subtle, the results suggest, at the very least, that early handling does not increase pain sensitivity in lambs and suggests there is still flexibility postnatally in the pain processing system of a precocial species.     

Acute cortisol responses of lambs to castration using a rubber ring and/or a castration clamp with or without local anaesthetic

Changes in plasma cortisol concentrations during the first 4 hours after castration of 6-week-old lambs by one of four methods were measured. The methods were application of a rubber ring above the testes, application of a ring to shorten the scrotum below the testes, use of a castration clamp plus a ring, and use of a castration clamp alone. The efficacy of local anaesthetic in reducing or abolishing the cortisol responses to castration by all these methods except short scrotum was assessed. Local anaesthetic was injected into the neck of the scrotum, both spermatic cords, the scrotal neck plus spermatic cords, or into both testes. The combined clamp plus ring method was used to test whether or not clamp damage to afferent nerves from the testes would reduce the cortisol response to ring castration. The short scrotum method elicited a significantly lower cortisol response than that caused by ring castration. Injection of local anaesthetic into both spermatic cords marginally reduced the cortisol response to ring castration, but the response was virtually abolished by prior scrotal neck, or scrotal neck plus spermatic cords, or intra-testicular local anaesthetic injections. The clamp plus ring method, where each spermatic cord and the associated scrotal tissue were crushed separately for 1, 5 or 10 seconds with no overlap between the two crush lines, did not elicit lower cortisol responses than the ring-only method. Local anaesthetic injected into the scrotal neck virtually abolished, and spermatic cord injections markedly reduced, the cortisol responses to combined clamp plus ring castration. The IO-second clamp application caused a more protracted cortisol response than did ring-only castration, whereas the cortisol responses to 1-second clamp application and to ring-only castration were similar. Local anaesthetic injected into the scrotal neck or spermatic cords did not affect significantly the cortisol response to the IO-second clamp application. The following conclusions were drawn from this work: the testes as well as the scrotum were sources of noxious sensory input after ring application; the clamp plus ring method used here was ineffective in reducing the pain-induced distress (as indicated by cortisol concentrations) caused by ring-only castration; injection of local anaesthetic into the scrotal neck or into the testes prior to ring application blocked most noxious sensory input from both the scrotum and the testes; and on the basis of the present cortisol responses the 10-second clamp applications method could not be recommended in reference to the ring-only method, but the l-second clamp application method might be equally acceptable for castrating 6-week-old-lambs. Of the methods examined, injections of local anaesthetic into the scrotal neck or both testes were the most effective in reducing the pain-induced distress caused by ring-only castration.     

Surveyed attitudes, perceptions and practices in Norway regarding the use of local anaesthesia in piglet castration

The last two years piglet castration in Norway has been performed by veterinarians and with the use of anaesthesia. In order to evaluate this new policy, veterinarians and pig producers were asked to fill out a questionnaire regarding their experiences with the new castration practices. The answers showed that the piglets were most often castrated using a combination of subcutaneous and intratesticular administration of lidocaine with adrenaline at an average age of 10 days. The effect of the anaesthesia was regarded as good by 54% of the veterinarians and 19% of the producers. Post-operative complications were rare. The overall evaluation showed that two-thirds of the veterinarians, but only one-third of the pig producers were satisfied or very satisfied with the implemented policy. However, while two-thirds of the pig producer had a negative attitude to the policy before it was implemented, only one-third were dissatisfied after two years experience.