Butorphanol and azaperone as a safe alternative for repeated chemical restraint in captive white rhinoceros (Ceratotherium simum)

Anesthesia in the white rhinoceros (Ceratotherium simum) has routinely invo lved potent narcotic anesthetic agents such as etorphine or carfentanil wit h their associated adverse side effects. In captive rhinoceroses conditione d to routine handling, a combination of butorphanol and azaperone at mean ( +/- SD) doses of 69.3 +/- 18.0 mg and 103.1 +/- 20.9 mg, respectively, was used to produce levels of neuroleptanalgesia ranging from light "standing" sedation to deeper planes of anesthesia producing sternal and lateral recum bency. This combination was used fur repeated (minimum repeat frequency of 3 days between events) anesthetic episodes (n = 26) in two animals, with th e remaining episode performed in a white rhinoceros with chronic renal dise ase. The action of butorphanol was satisfactorily reversed with naltrexone (125 mg i.v. and 125 mg i.m.). Results (mean +/- SD) include sternal recumb ency achieved in 14.1 +/- 8.1 min after i.m. dosing, standing and ambulatio n occurred in 1.7 +/- 0.6 min after reversal, heart rate was 62.0 +/- 10.1 beats/min, respiratory rate was 14.7 +/- 5.6 breaths/min and percentage of oxygen saturation of hemoglobin (Spo(2)) was 89.2 +/- 3.0%. Without supplem entation, the total elapsed time ranged from 44.9 min to 103.0 min, whereas Elapsed times up to 214.3 min were achieved with supplementation (mean tim e to supplementation was 28.0 +/- 13.9 min after initial dosing). Butorphan ol and azaperone produced adequate muscle relaxation and apparently adequat e analgesia for minor surgical interferences, including abdominal laparosco py. Respiratory rates and Spo(2) measurements were improved compared with r eports of using more potent opioids in this species.