A randomized clinical trial to compare ketamine-butorphanol-azaperone-medetomidine and detomidine-etorphine-acepromazine for anesthesia of captive Przewalski horses (Equus przewalskii).

This research evaluates the effectiveness of two anesthesia protocols, KBAM and DEA, on captive Przewalski horses. The results suggest that although DEA allows for faster induction and recovery, KBAM provides superior muscle relaxation and has less of an impact on oxygen levels during the maintenance phase.

Research Objective

The primary aim of this study was to compare the effectiveness of two anesthesia protocols, ketamine-butorphanol-azaperone-medetomidine (KBAM) and detomidine-etorphine-acepromazine (DEA), in Przewalski horses, a rare and endangered wild horse species. The key outcomes observed during the course of the research were the cardiorespiratory variables, quality of anesthesia, and recovery patterns.

Methodology

• A prospective randomized crossover trial was performed on ten adult Przewalski horses.
• Each horse was immobilized once with KBAM and once with DEA via remote dart injection. The anesthesia sessions were six months apart to avoid any overlap effect.
• The KBAM regimen included 200 mg of ketamine, 109.2 mg of butorphanol, 36.4 mg of azaperone, and 43.6 mg of medetomidine.
• The DEA regimen began with a 40 mg detomidine premedication, followed by 3.9 to 4.4 mg etorphine and 16 to 18 mg acepromazine 20 minutes later.
• Antagonists were administered for each protocol to reverse the effects of the anesthesia – for KBAM, 215 mg atipamezole and 50 mg naltrexone were used, whereas for DEA, 4 mg RX821002 and 100 mg naltrexone were utilized.

Results

• All horses were successfully anesthetized and recovered without any problems.
• Induction and recovery times were faster with the DEA protocol, but the quality of anesthesia during the maintenance phase was poorer compared to the KBAM protocol.
• Severe hypoxemia (low blood oxygen level), apnea (suspension of breathing), muscle rigidity, and tremors were observed in the horses anesthesia with DEA.
• In contrast, horses administered KBAM showed moderate hypoxemia, but the arterial oxygen pressures were higher compared to those treated with DEA protocol.

Conclusion

The study concluded that while DEA works faster in both the onset and recovery from anesthesia, KBAM offers superior muscle relaxation and less disturbance to oxygen levels, making it a potentially more suitable protocol for captive Przewalski horses. However, KBAM’s slower induction and recovery periods should be taken into consideration.