Abstract

The purpose of this study was to evaluate the combination of medetomidine (M), zolazepam and tiletamine (ZT) for immobilization of four species of Southeast Asian primates. Twenty-three immobilizations, including translocation of three free-ranging orangutans (Pongo pygmaeus pygmaeus), were performed at Sepilok Orangutan Rehabilitation Center and its surroundings in Sabah, Malaysia. Dosages of M 0.02–0.06 mg/kg and ZT 0.8–2.3 mg/kg IM produced a smooth induction without excitement and complete immobilization with good muscle relaxation within 1–7 min (x=4 min) in all four species. Heart and respiratory rates, ear canal and rectal temperatures, and systolic blood pressure were recorded every 10 min. Pulse rate and percent oxygen saturation of hemoglobin (SpO₂) trends were monitored continuously. Statistical analysis was performed for orangutans (n=12). No significant change over time occurred in heart rate, respiratory rate or SpO₂. Systolic blood pressure and body temperature decreased significantly during the immobilization. The only complication during all immobilizations occurred during translocation of one orangutan which developed hyperthermia and apnea, but it was successfully resuscitated. Atipamezole administered after 23–54 min (x=37 min), at five times the dosage of M, reversed the immobilization in all species. First signs of recovery were observed 3–27 min (x=10 min) after reversal. Medetomidine in combination with ZT and reversal with atipamezole was a safe and effective immobilization protocol for South-East Asian primates during clinical conditions at the dosages used in this study. As additional doses of ZT were required during all three translocations, further studies are needed to establish optimal dosage ranges of MZT for immobilization of free-ranging orangutans.

Acknowledgments

We thank the personnel at Sepilok Orangutan Rehabilitation Center for their assistance during the immobilizations; and Dr. Bengt Röken for useful advice concerning medetomidine use in wild animals. We also thank the Swedish University of Agricultural Sciences; the Faculty of Veterinary Medicine; and Orion Animal Health for supporting this study.