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.

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.

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.

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.