Chemical immobilization of chimpanzees (Pan troglodytes) using a combination of detomidine and ketamine

To determine if a combination of detomidine and ketamine can be used for effective chemical immobilization of chimpanzees.

Observational study.

Twenty-one adult captive chimpanzees (12 males, nine females), age 8-46 years, weighing 40.4-68.4 kg.

The chimpanzees were immobilized with intramuscular (IM) detomidine and ketamine by a darting system. Based on estimated weights, doses administered were 50 μg kg(-1) detomidine and 4 mg kg(-1) ketamine in groups 1 and 2, and 60 μg kg(-1) and 5 mg kg(-1) respectively in group 3. Eight minutes in group 1 and 15 minutes in groups 2 and 3 were allowed from the time of apparent immobilization before removing the animals from their enclosures. Body temperature, arterial haemoglobin saturation and pulse rate were measured. The time from injection to induction (recumbency and absence of voluntary movement), total anaesthetic and recovery times (with or without atipamezole) were recorded.

Immobilization occurred within 5 minutes after darting in most animals. Early handling of the chimpanzees often resulted in arousal and required further doses of ketamine IM. Most animals were hypoxaemic and hypothermic. Occasionally, bradycardia was observed. Atipamezole resulted in an acceptable quality of recovery 10 minutes after IM injection. The duration of immobilization varied widely when no antagonist was administered.

The combination detomidine (60 μg kg(-1) ) and ketamine (5-6 mg kg(-1) ) can be used for the immobilization of chimpanzees for non- to minimally invasive procedures. A period of 15 minutes should be allowed before handling to avoid unwanted arousal. Oxygen administration is recommended to reduce hypoxaemia. Administration of atipamezole is justified to hasten recovery.