Abstract

Chemical immobilization of non-domestic species can be challenging. For many species, only a few anesthetic protocols have been reported, and it becomes challenging when commonly used, reliable drugs are unavailable. This preliminary study describes the quality and physiological effects of a thiafentanil-ketamine-medetomidine and thiafentanil-medetomidine anesthesia combination in zoo-managed and free-ranging Equus caballus przewalskii, respectively. Forty anesthesia records of captive and 14 of free-ranging Przewalski horses from 1991–2017 were retrieved from Zoological Information Management System (ZIMS) electronic medical records. Thiafentanil dosages ranged 0.01–0.02 mg/kg when used in combination with medetomidine (dosage: 0.04–0.07 mg/kg) and ketamine (dosage: 0.25–1 mg/kg) and 0.02–0.025 mg/kg when used in combination with medetomidine alone (estimated dosage: 0.066 mg/kg). Authors found these combinations to generally induce rapid induction (captive range: 1–7 mins; wild range: 5–25 mins) and excellent muscle relaxation. Horses generally had stable physiological values including core body temperature (range: 96.5–103.9°F), although periods of apnea associated with low blood oxygen saturation were observed in some (range: 51–100%). No major anesthetic complications were observed in this study, demonstrating the safety and efficacy of the drug combinations for the capture and immobilization of zoo-managed and free-ranging Przewalski horses.

Acknowledgments

Thanks to Usukhjargal Dorj and staff Herrof Hustai National Park, Mongolia for coordination and assistance in all free-ranging Przewalski horse immobilizations.