CARDIORESPIRATORY EFFECTS OF VATINOXAN IN BLESBOK (DAMALISCUS PYGARGUS PHILLIPSI) IMMOBILIZED WITH THIAFENTANIL-MEDETOMIDINE.

Combinations of a low dose of opioid, such as thiafentanil, and a high dose of medetomidine, are increasingly being used for immobilization of African ungulates. Both drugs can have undesirable cardiorespiratory effects. In this study we assessed whether vatinoxan, a peripherally acting alpha2-adrenergic receptor antagonist, can be used to alleviate some of these effects without affecting the immobilization quality. Eight healthy, female, boma-confined blesbok (Damaliscus pygargus phillipsi), weighing a mean (SDtion) of 56.8 (4.4) kg, were immobilized twice in a randomized cross-over study with a 2-wk washout period using (1) 0.5 mg thiafentanil + 1.5 mg medetomidine (TM), (2) TM + vatinoxan: 0.5 mg thiafentanil + 1.5 mg medetomidine + 15 mg vatinoxan per milligram medetomidine (total of 22.5 mg, administered intramuscularly at 10 min post recumbency). Heart rate, respiratory rate, rectal temperature, oxygen saturation (SpO2), arterial blood pressure, and sedation scores from 1 to 5 (1 = limited effect; 5 = excessively deep) were measured every 5 min. Arterial blood gases (PaO2 and PaCO2) were measured at 10, 15, 25, and 35 min postrecumbency and the alveolar--arterial oxygen gradient (P[A-a]O2) was calculated. Induction times and immobilization quality did not differ between groups. The heart rate was significantly higher and the mean arterial pressure significantly lower in blesbok after receiving vatinoxan. All animals were hypoxemic and there were no significant differences in the respiratory rates, PaO2, PaCO2, SpO2, or P(A-a)O2 gradients at any time point. Although vatinoxan did not improve respiratory variables and blood oxygenation in these animals, the change in cardiovascular variables may suggest that it improves tissue perfusion, a positive outcome that requires further investigation.

Comparison of some cardiopulmonary effects of etorphine and thiafentanil during the chemical immobilization of blesbok (Damaliscus pygargus phillipsi).

OBJECTIVE: To determine the cardiopulmonary effects of etorphine and thiafentanil for immobilization of blesbok. STUDY DESIGN: Blinded, randomized, two-way crossover study. ANIMALS: A group of eight adult female blesbok. METHODS: Animals were immobilized twice, once with etorphine (0.09 mg kg-1) and once with thiafentanil (0.09 mg kg-1) administered intramuscularly by dart. Immobilization quality was assessed and analysed by Wilcoxon signed-rank test. Time to final recumbency was compared between treatments by one-way analysis of variance. Cardiopulmonary effects including respiratory rate (ƒR), arterial blood pressures and arterial blood gases were measured. A linear mixed model was used to assess the effects of drug treatments over the 40 minute immobilization period. Significant differences between treatments, for treatment over time as well as effect of treatment by time on the variables, were analysed (p < 0.05). RESULTS: There was no statistical difference (p = 0.186) between treatments for time to recumbency. The mean ƒR was lower with etorphine (14 breaths minute-1) than with thiafentanil (19 breaths minute-1, p = 0.034). The overall mean PaCO2 was higher with etorphine [45 mmHg (6.0 kPa)] than with thiafentanil [41 mmHg (5.5 kPa), p = 0.025], whereas PaO2 was lower with etorphine [53 mmHg (7.1 kPa)] than with thiafentanil [64 mmHg (8.5 kPa), p < 0.001]. The systolic arterial pressure measured throughout all time points was higher with thiafentanil than with etorphine (p = 0.04). The difference varied from 30 mmHg at 20 minutes after recumbency to 14 mmHg (standard error difference 2.7 mmHg) at 40 minutes after recumbency. Mean and diastolic arterial pressures were significantly higher with thiafentanil at 20 and 25 minute measurement points only (p < 0.001). CONCLUSIONS: Both drugs caused clinically relevant hypoxaemia; however, it was less severe with thiafentanil. Ventilation was adequate. Hypertension was greater and immobilization scores were lower with thiafentanil.

Comparison of cardiopulmonary effects of etorphine and thiafentanil administered as sole agents for immobilization of impala (Aepyceros melampus).

OBJECTIVE: To compare the cardiopulmonary effects of the opioids etorphine and thiafentanil for immobilization of impala. STUDY DESIGN: Two-way crossover, randomized study. ANIMALS: A group of eight adult female impala. METHODS: Impala were given two treatments: 0.09 mg kg-1 etorphine or 0.09 mg kg-1 thiafentanil via remote dart injection. Time to recumbency, quality of immobilization and recovery were assessed. Respiratory rate, heart rate (HR), mean arterial blood pressure (MAP) and arterial blood gases were measured. A linear mixed model was used to analyse the effects of treatments, treatments over time and interactions of treatment and time (p < 0.05). RESULTS: Time to recumbency was significantly faster with thiafentanil (2.0 ± 0.8 minutes) than with etorphine (3.9 ± 1.6 minutes; p = 0.007). Both treatments produced bradypnoea, which was more severe at 5 minutes with thiafentanil (7 ± 4 breaths minute-1) than with etorphine (13 ± 12 breaths minute-1; p = 0.004). HR increased with both treatments but significantly decreased over time when etorphine (132 ± 17 to 82 ± 11 beats minute-1) was compared with thiafentanil (113 ± 22 to 107 ± 36 beats minute-1; p < 0.001). Both treatments caused hypertension which was more profound with thiafentanil (mean overall MAP = 140 ± 14 mmHg; p < 0.001). Hypoxaemia occurred with both treatments but was greater with thiafentanil [PaO2 37 ± 13 mmHg (4.9 kPa)] than with etorphine [45 ± 16 mmHg (6.0 kPa)] 5 minutes after recumbency (p < 0.001). After 30 minutes, PaO2 increased to 59 ± 10 mmHg (7.9 kPa) with both treatments (p < 0.001). CONCLUSIONS AND CLINICAL RELEVANCE: The shorter time to recumbency with thiafentanil may allow easier and faster retrieval in the field. However, thiafentanil caused greater hypertension, and ventilatory effects during the first 10 minutes, after administration.

Immobilization of African buffaloes (Syncerus caffer) using etorphine-midazolam compared with etorphine-azaperone.

OBJECTIVE: To compare induction times and physiological effects of etorphine-azaperone with etorphine-midazolam immobilization in African buffaloes. STUDY DESIGN: Randomized crossover study. ANIMALS: A group of 10 adult buffalo bulls (mean body weight 353 kg). METHODS: Etorphine-azaperone (treatment EA; 0.015 and 0.15 mg kg-1, respectively) and etorphine-midazolam (treatment EM; 0.015 and 0.15 mg kg-1, respectively) were administered once to buffaloes, 1 week apart. Once in sternal recumbency, buffaloes were instrumented and physiological variables recorded at 5 minute intervals, from 5 minutes to 20 minutes. Naltrexone (20 mg mg-1 etorphine dose) was administered intravenously at 40 minutes. Induction (dart placement to recumbency) and recovery (naltrexone administration to standing) times were recorded. Arterial blood samples were analysed at 5 and 20 minutes. Physiological data were compared between treatments using a general linear mixed model and reported as mean ± standard deviation. Time data were compared using Mann-Whitney U test and reported as median (interquartile range) with p ≤ 0.05. RESULTS: Actual drug doses administered for etorphine, azaperone and midazolam were 0.015 ± 0.001, 0.15 ± 0.01 and 0.16 ± 0.02 mg kg-1, respectively. Induction time for treatment EA was 3.3 (3.6) minutes and not different from 3.2 (3.2) minutes for treatment EM. The overall mean arterial blood pressure was significantly lower for treatment EA (102 ± 25 mmHg) than that for treatment EM (163 ± 18 mmHg) (p < 0.001). The PaO2 for treatment EA (37 ± 12 mmHg; 5.0 ± 1.6 kPa) was not different from that for treatment EM (43 ± 8 mmHg; 5.8 ± 1.1 kPa). Recovery time was 0.8 (0.6) minutes for treatment EA and did not differ from 1.1 (0.6) minutes for treatment EM. CONCLUSIONS AND CLINICAL RELEVANCE: Treatment EA was as effective as treatment EM for immobilization in this study. However, systemic arterial hypertension was a concern with treatment EM, and both combinations produced clinically relevant hypoxaemia. Supplemental oxygen administration is recommended with both drug combinations.

EVALUATING THE USE OF A BUTORPHANOL-AZAPERONE-MEDETOMIDINE FIXED-DOSE COMBINATION FOR STANDING SEDATION IN AFRICAN ELEPHANTS (LOXODONTA AFRICANA).

This study investigated the use of a fixed-dose combination of 30 mg/ml butorphanol, 12 mg/ml azaperone, and 12 mg/ml medetomidine for the standing sedation of captive African elephants (Loxodonta africana). In total, seven females (mean age 19.6 yr; range 6-31 yr) and six males (mean age 33.5 yr; range 9-35 yr) were sedated. The estimated dose was 0.0005 ± 0.0001 ml/kg and 0.006 ± 0.001 ml/cm shoulder height, which resulted in a dose of 0.016 ± 0.002 mg/kg or 0.19 ± 0.04 mg/cm shoulder height butorphanol, 0.006 ± 0.0008 mg/ kg or 0.076 ± 0.015 mg/cm shoulder height azaperone, and 0.006 ± 0.0008 mg/kg or 0.076 ± 0.015 mg/cm medetomidine. First signs of sedation were observed within 3-10 min (mean 6 ± 2 min) after darting, and monitoring of the animals started on average at 24 ± 9 min after darting. No bradycardia was observed in any of the elephants (mean heart rate 40.0 ± 6.55 beats/min), although all the animals were mildly hypotensive (mean blood pressure 118.5/86 [94.5]). Rectal temperatures fell within acceptable ranges, and respiratory parameters were stable in all the animals throughout sedation and fell within the standard ranges reported for conscious, standing elephants. Only one elephant had clinically significant hypoxemia characterized by a partial pressure of oxygen (PaO2) < 60 mm Hg. This elephant was also hypercapnic (PaCO2 > 50 mm Hg), although pH and peripheral capillary oxygen saturation fell within acceptable ranges. None of the elephants reacted to moderately painful stimuli while sedated. The combination was reversed with intramuscular injections of naltrexone (1 mg for every 1 mg butorphanol) and atipamezole (5 mg for every 1 mg medetomidine). Recovery was smooth and calm in all the animals. Time from injection of the reversals until the first signs of recovery was 4.6 ± 2.01 min (range 1-8 min).

Immobilization quality and cardiopulmonary effects of etorphine alone compared with etorphine-azaperone in blesbok (Damaliscus pygargus phillipsi).

OBJECTIVE: To evaluate the immobilization quality and cardiopulmonary effects of etorphine alone compared with etorphine-azaperone in blesbok (Damaliscus pygargus phillipsi). STUDY DESIGN: Blinded, randomized, crossover design. ANIMALS: A total of 12 boma-habituated female blesbok weighing [mean ± standard deviation (SD)] 57.5 ± 2.5 kg. METHODS: Each animal was administered etorphine (0.09 mg kg-1) or etorphine-azaperone (0.09 mg kg-1; 0.35 mg kg-1) intramuscularly with 1-week intertreatment washout period. Time to first sign of altered state of consciousness and immobilization time were recorded. Physiological variables were recorded, arterial blood samples were taken during a 40-minute immobilization period, and naltrexone (mean ± SD: 1.83 ± 0.06 mg kg-1) was intravenously administered. Recovery times were documented, and induction, immobilization and recovery were subjectively scored. Statistical analyses were performed; p < 0.05 was significant. RESULTS: No difference was observed in time to first sign, immobilization time and recovery times between treatments. Time to head up was longer with etorphine-azaperone (0.5 ± 0.2 versus 0.4 ± 0.2 minutes; p = 0.015). Etorphine caused higher arterial blood pressures (mean: 131 ± 17 versus 110 ± 11 mmHg, p < 0.0001), pH, rectal temperature and arterial oxygen partial pressure (59.2 ± 7.7 versus 42.2 ± 9.8 mmHg), but lower heart (p = 0.002) and respiratory rates (p = 0.01). Etorphine-azaperone combination led to greater impairment of ventilatory function, with higher end-tidal carbon dioxide (p < 0.0001) and arterial partial pressure of carbon dioxide (58.0 ± 4.5 versus 48.1 ± 5.1 mmHg). Immobilization quality was greater with etorphine-azaperone than with etorphine alone (median scores: 4 versus 3; p < 0.0001). CONCLUSIONS AND CLINICAL RELEVANCE: Both treatments provided satisfactory immobilization of blesbok; however, in addition to a deeper level of immobilization, etorphine-azaperone caused greater ventilatory impairment. Oxygen supplementation is recommended with both treatments.

Pharmacokinetics and bioavailability after intramuscular injection of the 5-HT1A serotonin agonist R-8-hydroxy-2-(di-n-propylamino) tetralin (8-OH-DPAT) in domestic goats (Capra aegagrus hircus).

To determine the bioavailability and pharmacokinetic properties of the serotonin 5-HT1A receptor agonist R-8-OH-DPAT in goats, and 0.1 mg kg-1 R-8-OH-DPAT hydrobromide was administered intramuscularly (i.m.) and intravenously (i.v.) to six goats in a two-phase cross-over design experiment. Venous blood samples were collected from the jugular vein 2, 5, 10, 15, 20, 30, 40 and 60 min following treatment and analysed by liquid chromatography tandem mass spectrometry. Bioavailability and pharmacokinetic parameters were determined by a one-compartment analysis. Mean bioavailability of R-8-OH-DPAT when injected i.m. was 66%. The mean volume of distribution in the central compartment was 1.47 L kg-1 . The mean plasma body clearance was 0.056 L kg-1  min-1 . All goats injected i.v. and two of six goats injected i.m. showed signs of serotonin toxicity. In conclusion, R-8-OH-DPAT is well absorbed following i.m. injection and the observed pharmacokinetics suggest that administration via dart is feasible. Administration of R-8-OH-DPAT hydrobromide, at a dosage of 0.1 mg kg-1 , resulted in the observation of clinical signs of serotonin toxicity in the goats. It is suggested that dosages for the clinical use of the compound should be lower in order to achieve the desired clinical effect without causing serotonin toxicity.

Evaluation of butorphanol-azaperone-medetomidine in captive cheetah (Acinonyx jubatus) immobilization.

OBJECTIVE: The butorphanol-azaperone-medetomidine fixed-dose combination (BAM, respectively, 30-12-12 mg mL-1) with subsequent antagonism by naltrexone-atipamezole was evaluated for reversible immobilization of captive cheetahs (Acinonyx jubatus). STUDY DESIGN: Prospective, clinical trial. ANIMALS: Twelve cheetahs (six males and six females, weighing 37-57 kg) housed in enclosures, were immobilized at Hoedspruit Endangered Species Centre in the Republic of South Africa. METHODS: BAM volume dose rate was 0.009-0.014 mL kg-1 (mean ± standard deviation 0.010 ± 0.001 mL kg-1). Total dose in all animals was 0.5 mL. The actual doses were as follows: butorphanol (0.29 ± 0.04 mg kg-1), azaperone (0.12 ± 0.01 mg kg-1) and medetomidine (0.12 ± 0.01 mg kg-1). Physiologic variables and quality of immobilization were recorded every 5 minutes beginning at 15-20 minutes after darting. Arterial blood samples were collected three times at 20, 30 and 40 minutes after darting from all animals for analysis of blood oxygenation and acid-base status. RESULTS: The inductions were calm and smooth and mean induction time was 4.0 ± 1.1 minutes. Heart rate (50 ± 9 beats minute-1) and respiratory frequency (20 ± 3 breaths minute-1) were stable throughout immobilization. The recovery time after reversing with naltrexone and atipamezole was 9.1 ± 3.6 minutes. CONCLUSIONS: and clinical relevance BAM proved to be a reliable and cardiovascular stable drug combination for immobilization of cheetahs.

Dose-effect study of the serotonin agonist R-8-OH-DPAT on opioid-induced respiratory depression in blesbok (Damaliscus pygargus philipsi) and impala (Aepyceros melampus).

OBJECTIVE: To determine whether the R-enantiomer of 8-hydroxy-2-(di-n-propylamino) tetralin (R-8-OH-DPAT) alleviates respiratory depression in antelope species immobilized with etorphine. The experiment also aimed to establish the most clinically effective dose of this serotonin 5- HT1A receptor agonist. ANIMALS: A group of six female blesbok and six female impala. STUDY DESIGN: Each animal was subjected to four immobilization treatments in a prospective four-way crossover design-control treatment consisting of only etorphine at 0.09 mg kg-1 and three treatments consisting of etorphine at 0.09 mg kg-1 combined with 0.005, 0.02 and 0.07 mg kg-1 of R-8-OH-DPAT, respectively. Induction, quality of immobilization and recovery were monitored in each treatment. Physiological variables including heart rate, respiratory rate, arterial blood pressure and blood gases were measured for 35 minutes during immobilization. A linear mixed model was used to assess the effects of treatments over the recumbency period. RESULTS: R-8-OH-DPAT did not influence induction, immobilization or recovery scores. Respiratory rate in blesbok was increased in the medium- and high-dosage R-8-OH-DPAT treatment group. However, this increased respiratory rate did not translate into improvements of arterial partial pressure of oxygen (PaO2) values in the blesbok. The medium and higher dosages of R-8-OH-DPAT in impala led to an improved PaO2 as well as to decreased opioid-induced tachycardia during the first 10 minutes of immobilization. CONCLUSIONS AND CLINICAL RELEVANCE: Previous reports indicated that the racemic mixture of 8-OH-DPAT injected intravenously had a positive effect on blood-gas values in etorphine-treated hypoxemic goats. In this experiment, similar effects could be seen in impala at the higher dosage rates of R-8-OH-DPAT. However, failure to achieve an improvement of blood-gas values in blesbok was an unexpected result. It could be speculated that the dosage, species-specific differences of serotonin receptors or the use of the R-enantiomer of 8-OH-DPAT might play a role.

Evaluation of butorphanol-azaperone-medetomidine (BAM) in captive blesbok immobilization (Damaliscus pygargus phillipsi).

OBJECTIVE: The fixed-dose combination of butorphanol, azaperone and medetomidine (BAM; 30, 12 and 12 mg mL-1, respectively) with subsequent antagonism by naltrexone-atipamezole was evaluated for reversible immobilization of captive blesbok (Damaliscus pygargus phillipsi). STUDY DESIGN: Prospective, clinical trial. ANIMALS: Sixteen blesbok (four males and twelve females), weighing 52.5-71.0 kg, were immobilized in South Africa. METHODS: The total dose of BAM ranged from 0.5 to 0.7 mL for females and 0.7 to 0.9 mL for males. In seven animals chosen randomly, 8000 units of hyaluronidase was added to the dart. Physiologic variables were recorded every 5 minutes beginning at 10-20 minutes after darting. Arterial blood samples were collected three times at 20, 30 and 40 minutes after darting for analysis of blood acid-base status. RESULTS: The mean administered doses of BAM were as follows: butorphanol (0.34 ± 0.08 mg kg-1), azaperone (0.14 ± 0.03 mg kg-1) and medetomidine (0.14 ± 0.03 mg kg-1). The inductions were calm and smooth. The mean induction time was 9.6 ± 3.2 minutes with just BAM and 5.1 ± 0.8 minutes with BAM and hyaluronidase combination. Heart rate (45 ± 6 beats minute-1) and respiratory frequency (38 ± 4 breaths minute-1) were stable throughout immobilization. The mean arterial blood pressure for all animals was stable but elevated (137 ± 7 mmHg). Rectal temperature slightly increased over time but remained within an acceptable range. The recovery time after administering naltrexone and atipamezole was 4.8 ± 0.7 minutes. CONCLUSION AND CLINICAL RELEVANCE: The BAM combination proved to be reliable and effective in blesbok.

Evaluation of BAM (butorphanol-azaperone-medetomidine) in captive African lion (Panthera leo) immobilization.

OBJECTIVE: The combination of butorphanol, azaperone and medetomidine (BAM) with subsequent antagonism by naltrexone-yohimbine or naltrexone-atipamezole was evaluated for reversible immobilization of captive African lions (Panthea leo). STUDY DESIGN: Prospective, clinical trial. ANIMALS: Twenty lions, 11 males and nine females, weighing 38-284 kg were immobilized in South Africa. METHODS: The BAM volume dose rate administered was 0.005-0.008 mL kg-1 (0.6 mL 100 kg-1). Physiologic variables were recorded every 5 minutes. Four arterial blood samples were collected from all animals at 20, 30, 40 and 50 minutes after immobilization for analysis of blood-gases and acid-base status. RESULTS: The actual doses administered were as follows: butorphanol, 0.18±0.03 mg kg-1; azaperone, 0.07±0.01 mg kg-1; and medetomidine, 0.07±0.01 mg kg-1. The inductions were calm and smooth, and induction time ranged from 4 to 10 minutes (7±2 minutes). The amount of time needed to work with each lion was 70 minutes, and no additional drug doses were needed. Heart rate (40±8 beats minute-1) and respiratory frequency (15±4 breaths minute-1) were stable throughout immobilization. The mean arterial blood pressure of all animals was stable but elevated (142±16 mmHg). The rectal temperature slightly increased over time but remained within acceptable range. The recovery time was significantly shorter when using naltrexone and atipamezole (9±1 minutes) compared to using naltrexone and yohimbine (22±7 minutes). CONCLUSION AND CLINICAL RELEVANCE: The BAM combination proved to be reliable for general veterinary anaesthesia in lions. During anaesthesia, minor veterinary procedures such a blood collection, intubation, vaccination and collaring could safely be performed with no additional dosing required.

THE EFFECT OF A SLOW-RELEASE FORMULATION OF ZUCLOPENTHIXOL ACETATE (ACUNIL®) ON CAPTIVE BLUE WILDEBEEST (CONNOCHAETES TAURINUS) BEHAVIOR AND PHYSIOLOGICAL RESPONSE.

The study investigated the effect of a slow-release formulation of zuclopenthixol acetate (Acunil®) on blue wildebeest ( Connochaetes taurinus ) in captivity. Two groups of trials were conducted using either Acunil or a placebo (control). Animals (Acunil: n = 17; placebo: n = 12) were observed for a 12-hr period before the administration of Acunil or the placebo (pretreatment). After 24 hr, animals were administered Acunil (1.5 mg/kg) or a placebo (1.0-3.0 ml of sterile water) and observed again for 12 hr (posttreatment). During both treatments, animals were stimulated every 2 hr for 1 min by a person entering the enclosure (referred to as periods of stimulation). Behavioral observations and continuous heart rate, respiration rate, and motion measurements were taken throughout. Animals treated with Acunil spent more time lying with their heads folded back, eating and standing with their heads down, and less time being vigilant and exploring while walking around. Animals treated with the placebo also spent less time being vigilant and more time lying with heads up. Animals treated with Acunil groomed less while standing and performed less head shaking; no such changes were observed in the control group. Neither Acunil nor the placebo had any effect (P > 0.05) on heart rate. However, overall mean respiration rate was lowered (P = 0.02) when animals were treated with Acunil (pretreatment: 14.5 ± 0.82 breaths/min; posttreatment: 12.5 ± 0.83 breaths/min). Acunil also caused a lowered (P < 0.05) respiration rate during periods when animals were stimulated (pretreatment: 16.2 ± 0.87 breaths/min; posttreatment: 13.7 ± 0.87 breaths/min) and when animals were trotting and being vigilant. No such changes were observed with the placebo. Both placebo- and Acunil-treated animals spent more time being stationary during periods of stimulation. However, Acunil-treated animals also spent less time moving fast when they were stimulated.

EVALUATION OF ETORPHINE AND MIDAZOLAM ANESTHESIA, AND THE EFFECT OF INTRAVENOUS BUTORPHANOL ON CARDIOPULMONARY PARAMETERS IN GAME-RANCHED WHITE RHINOCEROSES (CERATOTHERIUM SIMUM).

Nineteen white rhinoceroses ( Ceratotherium simum ) were anesthetized with 4 mg of etorphine hydrochloride; 35-40 mg of midazolam; and 7,500 international units of hyaluronidase for dehorning purposes at a game ranch in South Africa, to investigate this anesthetic combination. Median time to recumbency was 548 sec (range 361-787 sec). Good muscle relaxation and no muscle rigidity or tremors were observed in 18 animals, and only 1 individual showed slight tremors. In addition, all animals received butorphanol i.v. 5 min after recumbency at the ratio of 10 mg of butorphanol per 1 mg of etorphine. Blood gas and selected physiologic parameters were measured in the recumbent animal, immediately before and 10 min after the administration of butorphanol. Statistically significant improvements were observed in blood gas physiologic and cardiopulmonary parameters 10 min after the administration of butorphanol, with a reduction in arterial partial pressure of carbon dioxide, systolic blood pressure, and heart rate and an increase in pH, arterial partial pressure of oxygen, oxygen saturation, and respiratory rate (all P < 0.005). After i.v. naltrexone reversal, recovery was uneventful, and median time to walking or running was 110 sec (range 71-247 sec). The results indicate etorphine and midazolam combination is an effective alternative anesthetic protocol and produces good muscle relaxation. Furthermore, i.v. butorphanol was associated with improved blood gas values and cardiopulmonary function for at least 10 min postinjection.

Validating a human biotelemetry system for use in captive blue wildebeest (Connochaetes taurinus).

We fitted two blue wildebeest (Connochaetes taurinus) with modified versions of the Equivital™ EQ02 wireless monitoring system to evaluate if the device could accurately measure heart rate and respiration rate in this species whilst anaesthetized as well as whilst fully conscious in captivity. Whilst under anaesthesia, we monitored each animal's heart rate and respiration rate using the Equivital™ biotelemetry belt, a Cardell(®) veterinary monitor and manual measurements. The animals were also administered doxapram hydrochloride (Dopram(®) ) and adrenaline intravenously at different times to stimulate changes in respiration and heart rate, respectively. Once 30 minutes of monitoring was completed, we reversed the anaesthetic and left the animals in captivity for 24 hours whilst wearing the Equivital™ belts. After 24 hr, we repeated the anaesthesia and monitoring as well as the administration of the doxapram hydrochloride and adrenaline. Intraclass Correlation Coefficients (ICC) calculated between all three monitoring methods showed moderate to excellent agreements for heart rate on both days (ICC: 0.73-0.98). ICCs calculated between the three methods for respiration rate showed good to excellent agreement between the Equivital belt and the other two methods (0.82-0.92) with the exception of occasions when only poor to fair agreements were found between the Cardell(®) measurements and manual measurements. Heart rate and respiration rate were also found to increase with motion while animals were in captivity. The results indicate that a modified version of the Equivital™ EQ02 system can be used as a potential biotelemetry device for measuring heart and respiration rate in captive blue wildebeest.

Validation of a LC-MS/MS method to simultaneously quantify thiafentanil and naltrexone in plasma for pharmacokinetic studies in wildlife.

Thiafentanil is a popular opioid agonist that is fully reversed by administering naltrexone. This agonist-antagonist combination is administered to a wide variety of wildlife species for chemical immobilisation, however plasma concentrations for thiafentanil remain unreported. This report describes a method that was developed and validated using human plasma and cross-validated for the analysis of goat plasma. Samples were extracted using a simple protein precipitation and analysed using LC-MS/MS. The assay was validated over the calibration range 4.38 - 1120 ng/mL for thiafentanil and 15.63 - 4000 ng/mL for naltrexone. The mean inter-day accuracies for QCs prepared in human plasma (n = 18) ranged from 94.8 - 103.8 % for thiafentanil and 94.8 - 95.9 % for naltrexone with corresponding precisions of 3.4 - 7.9 % and 2.8 - 11.4 %, respectively. The mean accuracies for QCs prepared in goat plasma (n = 6) ranged from 89.0 - 100.5 % for thiafentanil and 89.0 - 98.0 % for naltrexone with the associated precisions ranging from 7.1 - 11.6 % and 4.8 - 12.3 %, respectively. Both analytes were stable on bench for six hours and for three freeze-thaw cycles. The impact of heat-inactivation, necessary for the inactivation of potential foot-and-mouth disease, on analyte stability, matrix effect and recovery were evaluated, and a correction factor was established to determine the original analyte concentrations. The method was applied to pharmacokinetic samples collected from goats. The use of goats as a model species provides the first insight into the plasma concentrations of thiafentanil.

Evaluation of two different etorphine doses combined with azaperone in blesbok (Damaliscus pygargus phillipsi) immobilisation.

Chemical immobilisation is essential for veterinarians to perform medical procedures in wild African ungulates. Potent opioids combined with neuroleptic drugs are most often used for this purpose. The present study aimed at comparing the quality of immobilisation and effects on physiological variables between a high (high etorphine-azaperone [HE]: 0.09 mg kg-1) and low etorphine dose (low etorphine-azaperone [LE]: 0.05 mg kg-1), both combined with azaperone (0.35 mg kg-1), in 12 adult female boma-acclimatised blesbok. It was hypothesised that a reduction in etorphine's dose in combination with azaperone would result in less cardiorespiratory impairment but likely worsen the quality of immobilisation. Both treatments resulted in rapid induction and recovery times. Overall inter-treatment differences occurred in pulse rate (HE and LE: 52 ± 15 and 44 ± 11 beats minute-1, p 0.0001), respiratory rate (HE and LE: 15 ± 4 and 17 ± 4 breaths minute-1, p 0.006), partial pressure of exhaled carbon dioxide (HE and LE: 62.0 ± 5.0 and 60.0 ± 5.6 millimetre of mercury [mmHg], p 0.028) and arterial carbon dioxide (HE and LE: 58.0 ± 4.5 and 55.0 ± 3.9 mmHg, p 0.002). Both HE and LE led to bradycardia, hypertension and marked hypoxia to a similar extent. Furthermore, quality of induction, immobilisation and recovery were similar in both treatments. The role of azaperone in the development of cardiorespiratory compromise and gas exchange impairment that occurred when these combinations were used is still unclear. Further studies are recommended to elucidate drug- and dose-specific physiological effects in immobilised antelope.

Do potent immobilising-opioids induce different physiological effects in impala and blesbok?

Potent opioids are known to cause negative alterations to the physiology of immobilised antelope. How these effects differ between species has not been studied. This study aimed to compare time to recumbence and effects of opioid-based immobilisation on the physiology of impala (Aepyceros melampus) and blesbok (Damaliscus pygargus phillipsi). Eight animals of each species were immobilised, with 0.09 mg/kg etorphine and 0.09 mg/kg thiafentanil respectively, in a randomised two-way cross-over study. Variables measured and analysed by means of a linear mixed model included time to recumbence, heart rate, respiratory rate, arterial blood pressure, blood gases, lactate and glucose. In blesbok, mean time to recumbence was not significantly different with either drug (2.5 minutes and 2.2 min, respectively), but in impala thiafentanil achieved a shorter time to recumbence (2.0 min) than etorphine (3.9 min). Mean heart rates of immobilised impala were within reported physiological limits, but lower in immobilised blesbok when both opioids were used (35 beats/min to 44 beats/min vs. 104 ± 1.4 beats/min resting heart rate). Impala developed severe respiratory compromise and hypoxaemia from both opioids (overall mean PaO2 values ranged from 38 mmHg to 59 mmHg over 30 min). In contrast, blesbok developed only moderate compromise. Therefore, significantly different species-specific physiological responses to potent opioid drugs exist in blesbok and impala. Given that these different responses are clinically relevant, extrapolation of immobilising drug effects from one species of African ungulate to another is not recommended.

Intravenous butorphanol improves cardiopulmonary parameters in game-ranched white rhinoceroses (Ceratotherium simum) immobilized with etorphine and azaperone.

Abstract We immobilized 47 white rhinoceroses (Ceratotherium simum) for dehorning with 1-4 mg of etorphine HCl, 10-40 mg of azaperone, and 7,500 IU of hyaluronidase, at a game ranch in South Africa in November 2012. Forty-four received butorphanol intravenously 5 min after recumbency, at the rate of 10 mg of butorphanol per 1 mg of etorphine, and three animals did not. When possible, blood gas and physiologic parameters were measured immediately before butorphanol administration and 10 min later. Statistically significant improvements were observed, with a reduction in pH, partial pressure of carbon dioxide in arterial blood, heart rate, systolic blood pressure, and diastolic blood pressure, and with an increase in arterial partial pressure of oxygen, arterial hemoglobin oxygen saturation, and respiratory rate in animals administered butorphanol. In the three animals that did not receive butorphanol, no improvement was apparent. Butorphanol given to recumbent white rhinoceroses immediately after immobilization was associated with improved blood gas values and cardiopulmonary function for at least 10 min. Studies on the sustainability of these effects are necessary.