Evaluation of A Combination of Ketamine and Dexmedetomidine as A Field Anesethetic Protocol for Immobilization of Golden-Mantled Howler Monkeys (Alouatta palliata palliata).

BACKGROUND: The golden-mantled howler monkey (Alouatta palliata palliata) is an endangered primate experiencing acute population declines for reasons not fully identified. Health and disease monitoring are critical factors for understanding animal and ecosystem health, yet limited research has been achieved in this species due to difficulties in successful immobilization and sample collection. The purpose of this research is to investigate the efficacy of combined ketamine and dexmedetomidine in providing safe field anesthesia for golden-mantled howler monkeys (A. palliata palliata) to perform physical examinations and biological data collection.

METHODS: Eighteen free-ranging golden-mantled howler monkeys from the Marino las Baulas National Park in Costa Rica received a remote intramuscular injection of a ketamine-dexmedetomidine combination. Anesthetic timing intervals, cardiorespiratory parameters, and venous blood gases were evaluated.

RESULTS: Successful anesthesia was induced with mean doses of ketamine 8.65 mg/kg (±0.9) and dexmedetomidine 0.043 mg/kg (±0). Recoveries after reversal administration were rapid and smooth, with all animals successfully reintroduced to their colonies within 49 min (mean 38 min) of reversal administration.

CONCLUSIONS: Ketamine-dexmedetomidine combination is effective at inducing the appropriate anesthetic plane required for field work in this species and should be considered for in situ capture of free-ranging mantled howler monkeys.