Reversible Anesthetic Combination Using Medetomidine-Butorphanol-Midazolam in In Situ African Wild Dogs (Lycaon pictus)
In the past, there have been numerous drug combinations used to immobilize the African wild dog (Lycaon pictus) with varying success. Drug combinations that have been used include ketamine and xylazine,2 medetomidine and ketamine,6 tiletamine and zolazapam,2 and phencyclidine and ketamine1. The major disadvantage of these drug combinations is that at least one component of the combination is non-reversible leading to prolonged recovery times. This may be critical in immobilizing these animals in free-ranging settings as sedated wild dogs left alone may fall prey to other predators or loose contact with their pack. Additional drug combinations utilizing fentanyl and xylazine3,5 were fully reversible; however, PO2 levels were low and PCO2 levels were elevated.3,5 Thus, there is a need for a safe, fully reversible drug combination with rapid immobilization and good muscle relaxation. For field conditions, a drug combination that would last 30–40 minutes with a quick recovery time (<5 minutes) would be ideal. The aim of this investigation was to utilize a new combination of medetomidine, butorphanol, and midazolam to produce a 30–40 minute anesthesia that was fully reversible.
In this study three packs of enclosed African wild dogs, containing 23 males and 13 females, ranging in weight from 18.2–37.5 kg were utilized. The animals were anesthetized via remote injection and monitored with capnography, blood gas analysis, heart rate, respiratory rate, pulse oximetry, and blood pressure. Each wild dog was darted with a combination of medetomidine (mean±SD=44.5±9.1 µg/kg IM), butorphanol (0.24±0.06 mg/kg IM), and midazolam (0.29±0.11 mg/kg IM). The animals were then reversed with an intramuscular injection of atipamezole 3 mg, naltrexone 10 mg, and flumazenil 0.2 mg. Mean induction times (until the dog was laterally recumbent) were 6±5 minutes and total working time (from the time the dog could be handled until it was reversed) was 38±6 minutes.
The authors thank the Hoedspruit Endangered Species Centre and Juliette Erkestadt for their support of this project.
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