Reduction in pain suffered by lambs at castration

Efficacy of a single central injection of lignocaine at the scrotal neck on the behavioural response of lambs to castration

OBJECTIVE

To compare the behavioural responses of lambs to ring castration with or without local anaesthetic administration by single midline injection at the scrotal neck.

STUDY DESIGN

Blinded, randomized block design pen study.

ANIMALS

A group of 60 male Merino lambs; 6-8 weeks of age; average body weight of 18.5 ± 0.33 (mean ± standard error of the mean) kg at the time of castration.

METHODS

Lambs were randomly assigned to three groups of 20: 1) NUMNUTS - lamb placed in a marking cradle and ring castrated with 1.5 mL lignocaine 2%; 2) SHAM - lamb placed in marking cradle and the scrotum manipulated as though an elastrator castration ring were applied; and 3) RING - lamb placed in the marking cradle, ring castration performed using an elastrator. Pain-related behaviours annotated for 1 full minute every 5 minutes post-procedure, from video footage collected for 2 hours post-procedure, according to a defined ethogram.

RESULTS

Lignocaine administration led to significant (p < 0.05) reductions in restless behaviour at 5 and 10 minutes in NUMNUTS lambs compared with RING (mean = 0.2 ± 0.4 versus 1.0 ± 0.4, respectively) post castration. A significant (p = 0.01) reduction in foot stamping and kicking behaviour at 5 minutes post castration (mean = 1.5 ± 0.4, for RING versus 0.4 ± 0.4 for NUMNUTS) and significant (p = 0.001) reduction in the sum of all acute pain-related behaviours at 5 minutes post castration.

CONCLUSION AND CLINICAL RELEVANCE

A single midline injection of local anaesthetic at the scrotal neck can alleviate the behavioural responses to ring castration in the immediate post-procedure period. However, the duration of effect was limited, which may be a result of the drug we used. Development of a longer-lasting local anaesthetic formulation is imperative to optimize pain mitigation for ring castration.

Can Lambs in Pain Identify Medicated Feed?

Lambs in Australia undergo painful husbandry procedures as part of common husbandry. The magnitude and duration of pain are difficult to assess in lambs. Most currently used methods rely on behavioral expressions and physiological markers that may fail to detect the state of pain an animal experience. This study examined motivation of 12-week-old lambs experiencing chronic pain to self-medicate by consumption of feed containing an analgesic agent as an indicator of pain in lambs. In this study, 36 male Merino lambs were individually penned and acclimated to pelleted feed and two artificial odors: strawberry and banana. Once acclimated to odored feed, lambs were tested for their individual preference for the odors. Lambs were then assigned to one of two groups: Sham—sham handled day 0 and 7 or Ring—Ring castrated day 0 and tail docked day 7. To enable self-medication testing, lambs underwent a conditioning period (day 0–3) followed by the self-medication period (day 7–12). On day 0 lambs were castrated or sham handled, and then offered only medicated feed that contained an odor cue (either strawberry or banana). On day 7, lambs underwent tail-docking or sham handling and were offered both the conditioned medicated feed and non-medicated feed. Amount of each feed consumed was recorded 1 and 12 h after offer each day. Blood samples were taken for cortisol and white blood cell analysis and behavioral observations were recorded for 12 h following treatment. There was no difference in preference for medicated feed between Ring and Sham lambs during the self-medication phase (P = 0.18). Lambs in both groups displayed a significant preference for strawberry cued medicated feed during the self-medicated period when compared to the other testing periods (P = 0.05). Ring lambs displayed more active pain behaviors (mean = 15.1) than Sham (mean = 0.4, P &lt; 0.05). Following castration, Ring lambs had a higher neutrophil/lymphocyte ratio at 6, 24, 48, and 72 h. This study was not able to demonstrate that lambs can self-medicate for a state of pain.

Health and Welfare Survey of 30 Dairy Goat Farms in the Midwestern United States

Simple Summary

There appears to be a rapid expansion of dairy goat farming in the United States and the information available to producers on health, welfare, and production applicable to those in the Midwestern US is limited. This study intended to survey 30 dairy goat farms in the Midwestern US to provide insight into husbandry practices pertaining to health, welfare, and production, and to identify areas of future research. Pain relief for disbudding and castration, education and training programs, early kid management, and hoof trimming were identified as potential areas of future research. This study provided insight into the husbandry practices carried out on 30 dairy goat farms in the Midwestern US and areas of research to improve health and welfare.

Abstract

Dairy goat production in the Midwestern United States is increasing at a rapid rate and information on dairy goat husbandry practices applicable for producers in this region is limited. The objective of this study was to survey 30 dairy goat farms in the Midwestern US to provide insight into husbandry practices pertaining to health, welfare, and production, and to identify areas of future research. A questionnaire was developed and comprised 163 questions that were organized into categories including information on the producer (e.g., farming experience), staff, and goats (e.g., herd size, breed), housing, feeding and nutrition, milking practices and production, kid management, husbandry practices (e.g., disbudding, castration, hoof trimming), and health. Areas of future research that can improve goat health, production and welfare include pain relief for husbandry practices such as disbudding and castration, early kid management during birth to prevent illness/disease or mortality (e.g., warm and dry areas for kid rearing), eradication programs for common contagious diseases, training programs and education for claw trimming, disbudding, and udder health. In conclusion, this study provided insight into the husbandry practices carried out on 30 dairy goat farms in the Midwestern US and areas of research to improve health and welfare.

Nonsteroidal anti-inflammatory drugs affect the mammary epithelial barrier during inflammation

During inflammation of the mammary gland, the blood-milk barrier, which is predominantly composed of mammary epithelial cells, loses its integrity and gradients between blood and milk cannot be maintained. Nonsteroidal anti-inflammatory drugs (NSAID) are commonly used systemically in combination with local administration of antimicrobials in mastitis treatments of dairy cows to improve the well-being of the cow during the disease. However, the knowledge about their effects on the blood-milk barrier is low. This study aimed to investigate effects of different NSAID, with different selectivity of cyclooxygenase-inhibition, on the transepithelial electrical resistance (TEER) and capacitance, cell viability, and expression of tumor necrosis factor α of bovine mammary epithelial barriers in vitro. Primary mammary epithelial cells of 3 different cows were challenged with lipopolysaccharide (LPS) from Escherichia coli with or without addition of ketoprofen (1.25 mg/mL or 4 mM), flunixin meglumine (1.0 mg/mL or 4 mM), meloxicam (0.25 mg/mL, 0.75 mg/mL, or 4 mM), diclofenac (0.75 mg/mL or 4 mM) or celecoxib (0.05 mg/mL) for 6 h. Concentrations were adapted to comparable relations of the recommended dosage for systemic application. Additionally, a similar molar concentration of all NSAID was used. Lipopolysaccharide with or without NSAID induced a decrease in TEER within 5 h, which returned to control level within 14 h. Viability of cells challenged with LPS only was not affected. However, the cell viability was decreased with increasing concentrations of NSAID and this effect was amplified with simultaneous LPS challenge. Ketoprofen at both dosages, flunixin meglumine at 1.0 mg/mL, and meloxicam at 0.75 mg/mL accelerated the recovery of TEER in comparison to LPS only (return to control level within 9 h). The comparison of NSAID effects at the same molecular quantity of 4 mM showed different effect on the barrier in which ketoprofen accelerated the recovery after LPS-induced barrier opening, whereas meloxicam and diclofenac slowed down the recovery (return to control level after 24 h). In conclusion, NSAID do not prevent the mammary epithelial barrier opening by LPS; however, ketoprofen, flunixin meglumine, and meloxicam obviously support the re-establishment of the barrier integrity. Used in mastitis therapy at an optimized dosage the tested NSAID would likely support the recovery of milk composition. However, an overdose of NSAID would likely cause tissue irritation and in turn, a delayed recovery of the barrier permeability.

Development of a Donkey Grimace Scale to Recognize Pain in Donkeys (Equus asinus) Post Castration

The objectives of this study were to establish a donkey ethogram, followed by a donkey grimace scale to be applied to donkeys pre- and post-castration and to test if there was a notable difference in scores based on observer knowledge, gender, and experience, which could reveal possible discomfort/pain. Nine healthy male adult donkeys were surgically castrated. Fifty-four photos were selected from frontal, lateral, and body views taken pre- and post-castration. Observers ranging from minimal to extensive knowledge and levels of experience based on education and hours/month spent with donkeys scored six photos/donkey on a scale of 0-2 (0 = not present, 1 = moderately present, 2 = obviously present). Scores were based on body language and facial parameters: Ears down, ears back, eye white showing, glazed look, orbital tightening, eyes round shape, nostril tension, eyes narrow shape, muzzle tension, and abnormal stance and overall perception of the animal being in pain. Level of experience and knowledge, as well as gender significantly (p < 0.001), affected observers' ability to accurately score images. The study suggests that the most significant indicators of pain in donkeys are overall appearance and abnormal body stance provided their sensitivity, specificity and accuracy values of 63.18%, 62.07%, and 62.60%, respectively.

Benefits of a multimodal analgesia compared to local anesthesia alone to alleviate pain following castration in sheep: a multiparametric approach

Castration of male ruminants is a common livestock management practice, but induces pain. However, little is known about the effectiveness of multimodal analgesia compared to local anesthesia (LA) alone in reducing pain associated with burdizzo castration in sheep. This study aimed to monitor the pain response induced by castration in sheep and to assess the efficacy of analgesia strategies. Twenty-four 12-month-old male Texel sheep were burdizzo-castrated after administration of physiological serum (Burd), local anesthetic (Burd+LA) or LA plus non-steroidal anti-inflammatory drug (Burd+LA+NSAID). Sheep responses were monitored using behavioral and physiological indices of pain. Sampling occurred from 24 h pre-castration to 78 h post-castration, split into four periods based on the duration of analgesia: P0 (T-24 to T-1 h), P1 (T0 to T+2 h), P2 (T+3 to T+32 h) and P3 (T+36 to T+78 h). Behavioral indices were attention and head position, ear position, position of the eyelid, other facial expression, standing/lying postures, postures of the legs, clinical signs and abnormal activities. Physiological indices consisted in indicators of inflammation (haptoglobin, serum amyloid A (SAA), body temperature), hypothalamo-pituitary-adrenal axis (cortisol, non-esterified fatty acids, glucose), autonomous nervous system (heart rate variability (HRV)) and oxidative stress. The variables contributing most to discrimination of the period×treatment groups were analyzed by factorial discrimination analysis. Pre-castration (P0), there was no significant difference between treatments for all indicators (P > 0.05). Post-castration, eight indicators varied significantly according to period and treatment: cortisol, clinical signs, ratio of low frequency/high frequency (LF/HF) bands of the HRV, attention and head position, SAA, haptoglobin, body temperature and glucose. The treatment×periods groups were well discriminated by the 23 indicators. Burd in P0, Burd+LA in P0 and Burd+LA+NSAID in P0, P1 and P2 had low values for all indicators, likely reflecting absence of pain and discomfort. Burd in P1 and P2 and Burd+LA in P2 showed clinical signs and reduced attention, high LF/HF and high cortisol levels, reflecting acute pain. Burd and Burd+LA in P3 had high temperature, high haptoglobin, high glucose and high SAA, but no response from other pathways. These results suggest that (i) behavioral signs of pain were apparent up to 32 h post-castration, (ii) LA was partially effective, but only during its time of action (2 h) and (iii). multimodal analgesia (LA and NSAID) was effective for up to 3 days post-castration. These findings, and especially those related to sheep behavior, can help veterinarians and farmers better detect pain and refine their pain alleviation methods.

Analgesic effects of intravenous flunixin and intrafunicular lidocaine or their combination for castration of lambs

Objective

To analyse the effectiveness of intrafunicular lidocaine and intravenous flunixin for reducing pain and signs of stress in lambs undergoing surgical castration.

Design

Randomised controlled trial.

Setting

One university teaching hospital in Italy.

Participants

30 healthy male lambs, 9–12 weeks old.

Intervention

Allocation to five groups: a control group (C), undergoing general anaesthesia but not castration; a surgery group (S), undergoing orchiectomy without analgesic treatment; a surgery-lidocaine group (SL), undergoing orchiectomy and receiving intrafunicular 2 per cent lidocaine solution; a surgery-flunixin group (SF), undergoing orchiectomy and receiving intravenous flunixin; a surgery-flunixin-lidocaine group (SFL), undergoing orchiectomy and receiving both intrafunicular lidocaine and intravenous flunixin.

Main outcome measures

Nociception and stress were assessed through intraoperative indicators, serum cortisol concentration, glycaemia, behaviour, immune response and clinical evaluation of the heart rate (HR), respiratory rate and rectal temperature after surgery.

Results

Groups S and SL showed increased values of intraoperative HR, mean arterial pressure and postoperative cortisol concentration. In group SFL, cortisol values were similar to those of group C. No other difference could be detected.

Conclusions

The combination of intravenous flunixin and intrafunicular lidocaine reduced the pain and discomfort of lambs castrated under general anaesthesia. Intrafunicular lidocaine alone did not prevent pain or discomfort associated with castration.

Trial registration number

30/2012/CEISA/COM.

A pen study evaluation of buccal meloxicam and topical anaesthetic at improving welfare of lambs undergoing surgical mulesing and hot knife tail docking

Mulesing is a painful husbandry procedure commonly used to reduce the risk of breech strike in sheep. This study assessed the behavioural (over 6 h), cortisol, haptoglobin and haematology responses to surgical mulesing plus tail hot knife docking (mulesing); modulated by a buccal meloxicam formulation (Buccalgesic), a topical local anaesthetic wound dressing (Tri-Solfen) or both agents. 24 lambs were allocated to each of: 1) Placebo and sham handled (Sham); 2) Placebo and mulesing (Mules); 3) Buccalgesic and mulesing (Mules + B); 4) Tri-Solfen and mulesing (Mules + T); 5) Placebo, Tri-Solfen and mulesing (Mules + T + P); 6) Buccalgesic, Tri-Solfen and mulesing (Mules + T + B). Compared with Mules, Mules + T had a lower cortisol response (72.5 ± 8.7 nmol/L v 122.9 ± 8.7 nmol/L) at 30 min, reduced statue standing at 2 h (3.9% v 11.4%) and increased lying (20.9-25.0% v 7.3-12.5%). Mules + B had reduced cortisol response at 6 h (48.1 ± 8.5 nmol/L), reduced Neutrophil:Lymphocyte ratio at 6 h (Mules + B: 1.25; Mules: 2.44), reduced statue standing at 2 h and 4-6 h (4.1-8.3%), and increased lying at 5 h (27.4%). Mules + B + T had lower cortisol concentrations at 30 mins (86.51 ± 8.71 nmol/L), TWCC not significantly different from Sham at 6 h (9.07 vs 8.09) and 24 h (9.05 vs 8.38). Mules + T + B had significantly lower TWCC than Mules at 12 h (9.56 vs 11.05) and 24 h (9.05 vs 10.42). Mules + T + B did not.

Topical delivery of diclofenac into and across equine skin from a novel liquid diclofenac epolamine formulation

The aim was to investigate diclofenac delivery into and across equine skin in vitro using Franz diffusion cells from a novel diclofenac epolamine (DIC-EP; 1.3%) formulation and to compare the results to those of Surpass^® (1% diclofenac sodium liposomal cream) and a 1% aqueous solution of diclofenac sodium. Skin was harvested from the lower legs of Freiberger geldings immediately after slaughter and sliced to a thickness of ~2 mm. Skin samples were divided into two groups [Group 1: 1 year old (n = 2) and Group 2: 6-8 years old (n = 3)]. Cumulative permeation of diclofenac in Groups 1 and 2 after 24 h using diclofenac sodium solution was 1.91 ± 0.27 and 1.76 ± 0.34 μg/cm² , respectively. The values for Surpass^® and DIC-EP were 3.2 ± 0.8/3.3 ± 0.7 μg/cm² and 230 ± 59/89.2 ± 32.5 μg/cm² , respectively. Thus, diclofenac permeation from DIC-EP was significantly greater and appeared to show an age-dependent effect. Mathematical modelling showed that the DIC-EP formulation significantly increased diclofenac partitioning into the skin and a linear correlation was observed between steady-state flux and the partition parameter. Greater skin deposition of diclofenac was also observed with DIC-EP. These preliminary results suggest that the DIC-EP formulation may be effective in treating inflammatory conditions in horses.

The effect of isoflurane anaesthesia and vasectomy on circulating corticosterone and ACTH in BALB/c mice

The use of blood corticosterone and faecal corticosterone metabolites as biomarkers of post-surgical stress and pain in laboratory animals has increased during the last decade. However, many aspects of their reliability in laboratory mice remain uninvestigated. This study investigated serum corticosterone and adrenocorticotropic hormone (ACTH) in mice subjected to isoflurane anaesthesia and vasectomy, and mice subjected to isoflurane anaesthesia without surgery. Serum levels of corticosterone and ACTH after pre-treatment with dexamethasone were analysed to provide further information about the stress hormone profiles. Vasectomy resulted in an increase in corticosterone for at least four hours after surgery with a peak 30min after the mice regained righting reflex. Mice subjected to isoflurane anaesthesia without surgery had the highest level of serum corticosterone 5min after regained righting reflex and the level returned to baseline levels four hours after the procedure. In vasectomised mice, treated with dexamethasone, high levels of corticosterone remained 30min after the procedure, whereas the anaesthetised mice, treated with dexamethasone, had significantly lower levels of corticosterone compared to anaesthetised mice not treated with dexamethasone. Thus, dexamethasone effectively inhibited the corticosterone response in the anaesthetised-only mice, but not in the mice subjected to surgery. In conclusion, both isoflurane anaesthesia and vasectomy during isoflurane anaesthesia resulted in an increase in serum glucocorticoids, but the negative feedback mechanism of newly operated mice, was altered. This may have consequences for the interpretation of glucocorticoids measurements as a biomarker of post-surgical stress in mice.

Physiology and behavior of pigs before and after castration: effects of two topical anesthetics

Surgical castration of male piglets is a common management practice conducted on commercial swine farms to prevent the occurrence of boar taint and aggressive behavior. However, the procedure of surgical castration causes acute pain-induced distress, which is an animal welfare concern. The objective of this study was to evaluate the use of two topical anesthetics to alleviate the pain caused by castration in piglets as measured by physiological and behavior indices of stress. At 3 days of age, 40 weight-matched piglets were allocated to one of four treatment groups. Treatments included: (i) sham castration (CON), (ii) surgical castration (CAS), (iii) castration and short-acting local anesthetic applied topically to the castration wound (SHORT) and (iv) castration and long-acting local anesthetic applied topically to the castration wound (LONG). Blood samples were collected from piglets before and 30, 60, 120 and 180 min after castration to measure leukocyte and differential counts and cortisol concentrations. The above experiment was repeated without blood collection and behavior was recorded for 30 min before and 180 min after castration or handling. Stress vocalizations were recorded during castration and handling. All piglets were weighed before and 24 h after castration and wound healing was recorded daily for the first 14 days after castration. Leukocyte counts and differentials did not differ (P > 0.05) among any of the treatments. Cortisol concentrations were elevated (P < 0.06) in CAS, SHORT and LONG piglets compared with controls 30 and 60 min after castration. The percentage of stress vocalizations was greater (P < 0.05) among castrated piglets compared with CON piglets, regardless of anesthetic treatment. Piglets that were castrated and not given a topical anesthetic spent more time (P < 0.05) lying without contact compared with piglets castrated and given a topical anesthetic, regardless of the topical anesthetic administered. Body weight change did not differ (P > 0.05) among treatments 24 h after castration or control handling and wound healing scores were greater (P < 0.05) in SHORT compared with CAS and LONG piglets 9 to 14 days after castration. In this study, the use of a short- or long-acting topical anesthetic was not effective in reducing the pain-induced distress caused by castration in piglets. Further research is needed to evaluate alternative practical methods to reduce the pain caused by the on-farm castration of piglets.

Effect of intratesticular lidocaine on isoflurane requirements in dogs undergoing routine castration

OBJECTIVES

To evaluate the isoflurane sparing effect of intratesticular lidocaine administration in dogs undergoing castration.

METHODS

Thirty dogs received a standardised anaesthetic regimen including systemic analgesia with intramuscular buprenorphine at a dose of 0·02 mg/kg and intravenous carprofen at a dose of 4 mg/kg. Dogs were randomly assigned to a lidocaine group receiving 1 mg/kg lidocaine into each testis or a control group receiving no lidocaine. Baseline physiological parameters were measured after 10 minutes at an end-tidal isoflurane concentration of 1·3%. End-tidal isoflurane concentration was altered throughout surgery to maintain these parameters within 10% of baseline and recorded at five time points. T0 was baseline, T1 was the start of surgery, T2 to T3 were clamping of the testicular pedicles and T4 was skin closure. End-tidal isoflurane concentrations were compared using analysis of variance and Bonferroni tests.

RESULTS

Fifteen healthy dogs were included in each study group. End-tidal isoflurane concentration was significantly lower in the lidocaine group compared to the control group at T2 (P<0·01), T3 (P<0·01) and T4 (P<0·01).

CLINICAL SIGNIFICANCE

Intratesticular lidocaine reduces isoflurane requirements in dogs undergoing castration.

Behavioural responses of lambs to plastic clips as an alternative procedure to mulesing

OBJECTIVE

Compare the effects on the behaviour of lambs of applying occlusive plastic clips, as an alternative procedure to surgical mulesing, with tail docking, surgical mulesing and a control treatment.

PROCEDURE

We allocated 48 6-7-week-old Merino lambs to four treatment groups: plastic clips (Clip); surgical mulesing (Mules); tail docking with a rubber ring (Tail ring); no treatment (Control). For each posture and behaviour observed on each of the 4 days post-treatment, a Dunnett's multiple comparison test was used to simultaneously compare the Clip treatment with each of the comparator treatments (Control, Tail ring and Mules treatments).

RESULTS

Most of the significant differences (P < 0.05) detected between the comparator treatments occurred on day 1. For four of these measurements, the Clip treatment differed (P < 0.01) from the Mules treatment, but from not the Control and Tail ring treatments: the Clip lambs spent less time standing immobile not interacting with ground, hay or feeder, less time standing immobile head down not interacting with ground, hay or feeder, more time walking and more time interacting with ground, hay or feeder.

CONCLUSION

These behavioural results, together with previous behavioural and physiological research, indicate that the effect on lamb welfare of applying occlusive clips is less than that of surgical mulesing.

Behavior of piglets after castration with or without carbon dioxide anesthesia

Surgical castration of male piglets without anesthesia is a routine management practice conducted on commercial pig farms. For animal welfare reasons, it would be beneficial to develop methods of practical pain relief. The objective of this study was to evaluate the effect of providing CO₂ anesthesia before castration on the behavior of piglets for up to 8 d after castration in comparison with piglets castrated without anesthesia. In 3 successive replicates, the behavior of 186 male piglets castrated with (n = 95) or without (n = 91) anesthesia was observed for up to 8 d after castration. All piglets in a given replicate were castrated on the same day, before 8 d of age. Behavioral observations were carried out in accordance with a continuous focal sampling procedure that began immediately after castration and continued for a period of 1 wk. Barrows anesthetized with CO₂ before castration displayed more interactive behaviors during the overall observation period than the other barrows (P = 0.0412), which may indicate better welfare. Assessing all observation periods separately, differences in activity at the udder, lying, walking, and interactive behaviors appeared to support the beneficial effect of providing CO₂ anesthesia before castration. However, these differences varied over time between treatment groups. The most important conclusion was that piglets castrated with or without CO₂ anesthesia displayed behaviors indicative of pain and discomfort for up to 6 d after castration. Therefore, additional analgesia may be necessary to eliminate the long-term pain caused by castration even in piglets anesthetized with CO₂ before castration.

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.

A preliminary study of behaviour-based indicators of pain in cats

The aim of this preliminary study was to identify key behavioural indicators of pain in cats. The behaviour of cats before and after ovariohysterectomy was analysed using a detailed behavioural ethogram. A comparison of behaviours between cats given pre-operative analgesia only and cats given both pre- and post-operative analgesia indicated that both groups demonstrated changed behaviour following surgery, compared to a control group of cats which underwent anaesthesia but not surgery. However, some specific postures, such as ‘half-tucked-up’ and ‘crouching’, were identified that occurred with greater frequency in the cats receiving pre-operative analgesia only, as compared to those receiving additional post-operative analgesia. This indicates that there are some key behaviours that may be useful in determining pain in cats. Routine administration of pre- but not post-operative analgesia may be ineffective for adequately alleviating pain in cats.

The effect of a topical anaesthetic formulation, systemic flunixin and carprofen, singly or in combination, on cortisol and behavioural responses of Merino lambs to mulesing

OBJECTIVE

To determine the pain responses of lambs to mulesing, and the effectiveness of potential analgesic treatments.

PROCEDURES

Merino lambs (n=64) were allocated at 5 weeks of age to eight treatment groups: 1) sham mules; 2) conventional mules; 3) topical anaesthetic, incorporating lignocaine, bupivicaine, adrenaline and cetrimide, applied immediately after mulesing; 4) flunixin + topical anaesthetic, with flunixin administered 2.5 mg/kg s.c. 90 min before mulesing; 5) carprofen + topical anaesthetic, with carprofen administered 4 mg/kg s.c. 90 min before mulesing; 6) carprofen, administered as above; 7) flunixin, administered as above; and 8) carprofen + flunixin, administered as above. Plasma cortisol was measured at 0, 0.5, 6, 12 and 24 h relative to mulesing. Animal behaviour, including posture, was recorded for 12 h after mulesing.

RESULTS

The conventional mules lambs exhibited large increases in plasma cortisol, reduced lying and increased standing with a hunched back compared with sham mules animals. Topical anaesthetic reduced the cortisol peak to mulesing and hunched standing, and increased lying compared with the conventional mules treatment, but generally did not result in values equivalent to sham mules animals. Carprofen, flunixin, and carprofen + flunixin treatments did not reduce the cortisol response to mulesing but substantially ameliorated some changes in behavioural postures. Flunixin + topical anaesthetic reduced the cortisol peak following mulesing and substantially ameliorated most changes in behavioural postures. Carprofen + topical anaesthetic abolished the cortisol peak following mulesing and substantially ameliorated most changes in behavioural postures. All mulesed animals lost weight in the week after mulesing regardless of analgesic administration, but there were no significant differences in growth rate between any of the eight treatments over the 3 weeks after mulesing.

CONCLUSIONS

Analgesics can moderate the pain response of lambs to mulesing. The welfare outcome for lambs of mulesing could be improved by use of a combination of local anaesthetic and long acting non-steroidal anti-inflammatory drug.

Effects of vasectomy surgery and meloxicam treatment on faecal corticosterone levels and behaviour in two strains of laboratory mouse

Behaviour was assessed in 32 C57BL/6JCrl and 32 C3H/HeN male mice 1 h following vasectomy; saline or meloxicam was administered 30 min prior to surgery at 5, 10, or 20 mg kg(-1). Faeces were collected 24 h prior to, and 3, 6, 9, 12, 24 h following, vasectomy for measurement of faecal corticosterone. Peak corticosterone levels were significantly higher in mice that underwent vasectomy and received saline (p<0.001) or meloxicam at 5 or 10 mg kg(-1) (p=0.021, and p<0.001, respectively) compared with normal un-operated controls. Mice that underwent vasectomy and received 20 mg kg(-1) meloxicam had peak corticosterone levels that were not different from normal un-operated mice (p=0.254). Discriminant analysis was used to identify behaviours responsible for group separation; these were summed to create two behaviour scores. Score 2 (the frequency of flinching, writhing, rear leg lift and press 2) was thought to be pain related; mice that underwent vasectomy and received saline exhibited significantly more of these behaviours than the normal controls (p=0.032), and the mice that received meloxicam (at any dose). Strain differences were observed in both the stress response to vasectomy and the behavioural changes; the C3H/HeN mice had higher pain scores (behaviour Score 2) and peak corticosterone responses than the C57BL/6JCrl mice. We have demonstrated that significant changes occur in the behaviour of mice following vasectomy, and these changes are reduced by use of meloxicam. Vasectomy elicits a rise in corticosterone levels that was only reduced by the highest dose of meloxicam.

Pharmacokinetics of diclofenac in sheep following intravenous and intramuscular administration

OBJECTIVES

The aim of this work was to examine the pharmacokinetics of diclofenac (DCLF) in sheep after intravenous (IV) and intramuscular (IM) dosing.

ANIMALS

Healthy male Najdi sheep.

MATERIALS AND METHODS

Diclofenac (1 mg kg(-1)) was administered to ten clinically healthy-male Najdi sheep IV or IM (n = 5 each). Blood samples (5 mL) were collected and serum was separated for drug analysis by high-performance liquid chromatography with UV detection. Diclofenac pharmacokinetic parameters were determined by noncompartmental analysis.

RESULTS

Diclofenac is quickly eliminated from sheep with a terminal T(1/2lambda) of 2-3 hours for both routes of administration. Total DCLF clearance after IV and IM administration was 87.86 +/- 24.10 and 85.69 +/- 40.76 mL kg(-1) hour(-1) respectively. The absolute bioavailability of IM DCLF appears to be approximately 100%.

CONCLUSIONS AND CLINICAL RELEVANCE

The drug should be administered two to three times daily in sheep by IM or IV injection to maintain therapeutic concentrations. Additional studies are needed to evaluate the route of elimination of DCLF in sheep including metabolites formation and the significance of enterohepatic circulation.

Castration of lambs: a welfare comparison of different castration techniques in lambs over 10 weeks of age

Seventy male lambs over 10 weeks of age were castrated using Burdizzo, rubber rings, or surgery to assess the acute and long-term effects of castration. All castrations were performed under local anaesthesia. The surgically castrated lambs were additionally sedated with xylazine and the sedation reversed with tolazoline. The frequency of abnormal postures and immediate behavioural responses indicated that surgically castrated lambs were most distressed; the lambs castrated using Burdizzo and rubber rings were not dissimilar to those of the control group. Between 1.5 and 9h after castration, signs of pain and distress were at a lower level in lambs anaesthetised with bupivacaine compared with those treated with lidocaine. Due to the markedly faster wound healing, Burdizzo castration seemed to be preferable (fewer signs of long-term pain) when compared to the rubber ring technique. It was concluded that local anaesthesia with bupivacaine, followed by the Burdizzo method is the preferable technique for the castration of lambs older than 10 weeks of age.

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.

Differences in the acute pain responses of two breeds of lamb following castration and tail docking with the rubber ring method

Charolais × and Suffolk × Mule lambs of less than one week of age were castrated and tail docked using a standard rubber ring technique. After these procedures, their behaviour was monitored for I h. Their respiration rates and scrotal sac measurements were also recorded. Both breeds of lamb exhibited abnormal behaviour patterns following these procedures. The recumbent behaviour pattern of both breeds was remarkably similar but their standing behaviour differed markedly. The Charolais × lambs were significantly more active and had significantly higher respiration rates compared with the Suffolk × lambs. They also took a greater amount of time to recover to a normal posture. Their abnormal behavioural responses suggested that both breeds of lamb experienced acute pain following castration and tail docking, but the type of behaviour exhibited was breed-dependent. The findings suggest that different breeds of lamb may experience different levels of distress in response to the same husbandry procedure. Alternatively, they may simply reflect a difference in the character and temperament of the breeds studied.

Preliminary evaluation of a behaviour–based system for assessment of post–operative pain in horses following arthroscopic surgery

OBJECTIVE

To develop a method for objective assessment of equine post-operative pain.

STUDY DESIGN

Prospective nonblinded clinical study.

ANIMALS

Twelve adult horses: Group 1 (G1, n = 6), admitted for arthroscopy (under general anaesthesia, with multimodal analgesia); Group 2 (G2, n = 6), 'pain free' controls.

MATERIALS AND METHODS

Horses were filmed continuously (CVI, time-lapse video recorder) over 72 hours, from 24 hours pre-surgery (PS) to 48 hours post-recovery (PR) (G1), and over 24 hours (G2). Activity budgets were determined from 24 to 0 hours PS, 0-24 and 24-48 hours PR (G1) and for 24 hours (G2). Using direct observation (DO), active behaviours and postures were recorded at set time points PS and PR (G1) and at two time points (morning/evening) (G2). Heart rate (HR) and respiration rate (RR) were recorded simultaneously. Statistical analysis investigated within-group and between-group time-related changes in behaviour, HR and RR.

RESULTS

There was no difference in HR or RR between G1 and G2 at any time point. Anaesthetic 'hangover' and hunger-related activity modulated behaviour from 0 to 6 hours PR, when abnormal postures and locomotion occurred in all G1 horses, but no G2 horses. Compared with G1 (0-24 hours PR), G2 spent more time eating (t = -3.34, p < 0.01), more time at the front of the stable (t = -2.42, p < 0.05), and less time exhibiting 'abnormal' behaviour (U = 56, p < 0.01). Comparing PS and PR behaviour, G1 spent less time exploring from 24 to 48 hours PR (t = 3.49, p < 0.05), less time in sternal recumbency (t = -3.8, p < 0.05) and less time moving (t = 3.19, p < 0.05). Horses tended (p < 0.07) to spend less time positioned in the front of the stable PR (less from 24 to 48 hours PR than from 0 to 24 hours PR). Comparing PR (evening) behaviour, G2 spent more time with head above withers (U = 21.5, p < 0.01), and ears forwards (U = 22, p < 0.01). G1 showed time-related changes (all p < 0.05) in time with lower lip tense (S = 15.8), eating (S = 17.08) and with head positioned above withers (S = 18.04). No differences in event behaviours were observed between G1 and G2. Within G1, only olfactory behaviour varied significantly with time (S = 14.52, p < 0.05).

CONCLUSIONS

Changes in equine behaviour suggestive of post-operative discomfort were identified using both DO and CVI. Analysis of activity budgets may be a more sensitive method of identifying behavioural changes indicative of equine discomfort than repeated DO of specific events and postures.

Effect of repeated ketoprofen administration during surgical castration of bulls on cortisol, immunological function, feed intake, growth, and behavior

To determine the effect of repeated ketoprofen (K) administration to surgically castrated bulls on cortisol, acute-phase proteins, immune function, feed intake, growth and behavior, 50 Holstein x Friesian bulls (11 mo old; 300 +/- 3.3 kg) were assigned to one of five treatments: 1) untreated control (C); 2) surgical castration at 0 min (S); 3) S following an i.v. injection of 3 mg/kg of BW of K at -20 min (SK1); 4) S following 1.5 mg/kg of BW of K at -20 and 0 min (SK2); or 5) S following 1.5 mg/kg of BW of K at -20 and 0 min and 3 mg/kg of BW of K at 24 h (SK3). Castration acutely increased plasma cortisol concentrations in S- and K-treated animals compared with C, with no differences in peak and interval to peak cortisol responses among the castration groups. Overall, the integrated cortisol response was greater (P < 0.05) in the castrates than in C, whereas K treatments decreased (P < 0.05) this response compared with S alone, with no differences between K treatments. Plasma haptoglobin and fibrinogen concentrations were increased (P < 0.05) on d 3 in the castration groups compared with C as the result of tissue trauma induced by castration, whereas SK1 and SK2 had lower (P < 0.05) haptoglobin concentrations than S animals. On d 1, concanavalin A-induced interferon-gamma production was suppressed (P < 0.05) in S and SK3 compared with C, SK1, and SK2 animals. Overall from d 1 to 33, DMI were lower (P < 0.05) in S, SK1, and SK3 than in C animals. From d -1 to 35, ADG were lower (P < 0.05) in S, SK2, and SK3 compared with C animals. A higher (P < 0.05) incidence of standing postures and lower incidence of lying postures was observed in S compared with C during the first 6 h after treatment. However, the higher (P = 0.02) incidence of abnormal standing activities observed for S was reversed (P < 0.05) by the K treatments. In conclusion, surgical castration increased plasma cortisol and acute-phase proteins and decreased immune function, feed intake, and growth rate. Ketoprofen effectively reduced the cortisol response to castration, but there was no advantage in treating with two split doses of K (1.5 mg/kg of BW per dose). A repeated K dose 24 h after treatment (3 mg/kg of BW) had no influence on changes in acute-phase proteins and immune response. Systemic analgesia with K is an effective method for alleviating acute inflammatory stress associated with castration.

Effect of ketoprofen, lidocaine local anesthesia, and combined xylazine and lidocaine caudal epidural anesthesia during castration of beef cattle on stress responses, immunity, growth, and behavior

To determine the effects of burdizzo castration alone or in combination with ketoprofen (K), local anesthesia (LA), or caudal epidural anesthesia (EPI) on plasma cortisol, acute-phase proteins, interferon-gamma production, growth, and behavior of beef cattle, 50 Holstein x Friesian bulls (13 mo old, 307 +/- 5.3 kg) were assigned to (n = 10/treatment): 1) control (handled; C); 2) burdizzo castration (B); 3) B following K (3 mg/ kg of BW i.v.; BK); 4) B following LA (8 mL into each testis and 3 mL s.c. along the line where the jaws of the burdizzo were applied with 2% lidocaine HCl; BLA); and 5) B following EPI (0.05 mg/kg of BW of xylazine HCl and 0.4 mg/kg of BW of lidocaine HCl as caudal epidural; BEPI). The area under the cortisol curve against time was lower (P < 0.05) in BK than in B, BLA, or BEPI animals. On d 1 after treatment, plasma haptoglobin concentrations were higher (P < 0.05) in B, BLA, and BEPI than in BK animals. On d 3, haptoglobin and plasma fibrinogen concentrations were higher (P < 0.05) in all castration groups than in C. On d 7, haptoglobin and fibrinogen concentrations remained higher (P < 0.05) in BLA than in B and C animals. On d 1, concanavalin A-induced interferon-gamma production was lower (P < 0.05) in B, BLA, and BEPI than in C, but there was no difference between BK and C animals. From d -1 to 35, ADG was lower (P < 0.05) in B, BLA, and BEPI animals, but not in BK compared with C animals. Overall, there was a higher (P < 0.05) incidence of combined abnormal postures in B than in C, BK and BEPI animals. Although the use of K and EPI decreased (P < 0.05) these postures compared with B alone or B with LA, there was no difference between the K and EPI treatment. In conclusion, burdizzo castration increased plasma cortisol and acute-phase proteins, and suppressed immune function and growth rates. Local anesthesia prolonged the increase in acute-phase proteins. Ketoprofen was more effective than LA or EPI in decreasing cortisol and partially reversed the reduction in ADG following castration. The use of K or EPI was more effective than LA in decreasing pain-associated behavioral responses observed during the first 6 h after treatment. Systemic analgesia with ketoprofen, a non-steroidal antiinflammatory drug, was more effective in reducing inflammatory responses associated with castration than LA or EPI.

Assessing Pain in Animals

Assessing the experience of pain in animals is a difficult task, yet one that is important in animal welfare research. Some approaches to pain assessment in animals are reviewed here. General qualities of pain scales and specific parameters suitable for clinical and experimental pain assessments are discussed. It is argued that pain assessment will progress through an integration of objective and subjective observations of behaviour coupled with multiple measures in various other areas. Such multidimensional pain scales allow an adequate characterisation of the complexity of an individual animal's pain experience to be made. This knowledge improves the recognition and treatment of pain and will allow informed moral debate on the acceptability of practices such as castration and tail-docking of lambs.

Analgesia of newborn lambs before castration and tail docking with rubber rings

This study assessed the effects of suckled sucrose and parenteral carprofen treatment on behavioural measurements of discomfort and serum haptoglobin concentration in lambs following rubber ring castration and/or tail docking. Twenty-eight male and 20 ewe lambs were allocated to either a male or ewe lamb control group (n=4) or to one of three male and two ewe lamb treatment groups (n=8). Male lambs in one treatment group received carprofen subcutaneously (0.5 mg/kg) 30 minutes before castration and docking. Lambs in all other treatment groups suckled sucrose or colostrum immediately before castration and/or tail docking. Behavioural measurements of discomfort were made following castration or tail docking in treatment groups and also in control animals which were not castrated or tail docked. Blood sampling of animals in treatment groups for analysis of serum haptoglobin, an acute phase protein used as an indicator of an acute inflammatory response, was performed before castration or docking and at 24 and 48 hours after castration or docking. Control lambs were blood sampled at 0, 24 and 48 hours following behavioural assessment Neither suckled sucrose nor carprofen treatment altered discomfort behaviour associated with castration or tail docking. Haptoglobin levels following castration or tail docking remained close to the detection limits of the assay and were similar to those recorded in control animals.

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.

Comparison of methods for the reduction of acute pain produced by rubber ring castration or tail docking of week-old lambs

Behavioural and plasma cortisol changes were recorded for groups of eight Suffolk x Greyface lambs subjected to castration or tail docking using rubber rings with and without local anaesthetic treatment. Immediately after application of the rubber ring, local anaesthetic (2 x 0.2 ml 2% lignocaine) was administered either by needle and syringe or by high-pressure needleless injection into each side of the neck of the scrotum or tail at the site of the ring, or by high pressure needleless injection into the testes before ring application. In other groups, the innervation to the scrotum or tail was disabled by crushing with a powered bloodless castrator just proximal to the ring. Measurements were recorded in groups of control (handled) lambs, with and without local anaesthetic treatment. Application of local anaesthetic by high pressure needleless injection had little effect on either plasma cortisol values or behaviour of control lambs. For castration, application of the bloodless castrator and/or local anaesthetic at the ring site reduced the peak plasma cortisol concentration by 50% (P < or = 0.01), the incidence of active behavioural responses by 80 and 64% (P < or = 0.01) respectively, and the time spent in abnormal postures by 68 and 59% (P < or = 0.01) respectively. Both methods were effective in reducing pain for tail docking [active behavioural responses reduced by more than 80% (P < or = 0.01) and abnormal postures by 56% (P < or = 0.01)], although local anaesthetic was more effective, reducing the peak cortisol by 60% (P < or = 0.01) [crushing by 44% (P > 0.05)]. Injection of local anaesthetic into the testes was less effective than injection into the neck of the scrotum at the site of the ring [reduction in abnormal lying postures (P < or = 0.05), 45 vs 71%, respectively]. The rapid action, effectiveness, and ease of application of these experimental methods may provide the basis for commercially viable methods for reducing the acute pain produced by rubber ring castration and tail docking of lambs.

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.

Effects of four analgesic treatments on the behavioural and cortisol responses of 3-week-old lambs to tail docking

The behavioural and cortisol responses of groups of seven or eight lambs were used to determine which of three methods of tail docking (rubber ring, Burdizzo and rubber ring combined, or heated docking iron) produced the least signs of pain in the first 3 h after use and which of four analgesic treatments (1.0 ml bupivacaine subcutaneously, 0.5 ml bupivacaine epidurally, a topical cold analgesic spray or diclofenac 1.5 mg kg-1) was most effective in reducing these signs. Amputation with a heated docking iron produced levels of behaviour and cortisol responses which did not differ markedly from those of handled controls. The rubber ring method produced the greatest increase in all parameters (total active behaviour 110 +/- 91 counts; 51 +/- 23 min spent in abnormal postures; peak cortisol 93 +/- 51 nmol l-1). Subcutaneous bupivacaine, administered immediately prior to application of the ring, appeared to be the analgesic treatment most effective at reducing these responses (23 +/- 15 counts; 24 +/- 22 min.; 44 +/- 20 nmol l-1).