Abstract

Twelve healthy markhors (Capra falconeri heptneri) (four male, eight female) were immobilized a total of 16 times for routine procedures in the Helsinki Zoo between March 2000 and October 2003 with a combination of medetomidine (MED: 120.8±37.7 µg/kg [mean ± SD]) and ketamine (KET: 1.5±0.5 mg/kg). Prior to darting, the stress (SS) exhibited by the target animal(s) was scored. The animals were then assessed for either a sufficient or insufficient level of anesthesia (LA), depending on whether they required additional anesthetics (propofol at 1.2±0.5 mg/kg IV or half of the original dose of MED-KET IM) in order to achieve a satisfactory immobilization. Paired venous and arterial samples were taken at T₁=23.7±6.6 and T₂=50.2±7.4 minutes (from dart impact) for serum cortisol concentration (S-COR) and blood gas analysis, respectively.

Animals requiring additional anesthetics had higher stress scores prior to being darted (p<0.01). S-COR did not correlate with SS or arterial PaO₂. In addition, a significant reduction in S-COR over time between paired samples was found (p<0.01). Preliminary results suggest that acute stress cannot be measured with S-COR in Markhors when a MED-KET combination is used for chemical immobilization. Propofol proved to be an efficient and safe method for inducing an adequate plane of anesthesia when the original anesthetic response was regarded as insufficient for a satisfactory immobilization. We conclude that in order to achieve an optimal anesthetic response in markhors immobilized with MED-KET, acute preanesthetic stress should be avoided.