Comparison of two protocols for field immobilization of white-eared opossums (Didelphis albiventris)
The aim of this study was to investigate the efficacy of two protocols for field immobilization of white-eared opossums (Didelphis albiventris) and compare their effects on immobilization, cardiopulmonary variables, and recovery times. Twenty one opossums were randomly divided into two groups; G1 received ketamine (15 mg kg−1)-dexmedetomidine (0.15 mg kg−1) intramuscularly (IM) and G2 received the ketamine-dexmedetomidine combination and isoflurane once induction was achieved. Oxygen was delivered by face mask (1.5 L minute−1). Thirty minutes after induction, isoflurane was discontinued (G2) and both groups were administered atipamezole (1.5 mg kg−1) IM. Respiratory (ƒR) and heart rate (HR), oxyhemoglobin saturation (SpO2), and rectal temperature (T) were recorded every 5 min. Induction time, time to first movement (RT1), and time to achieve standing (RT2) were recorded. ANOVA and non-parametric tests were used. Level of immobilization was assessed by observation of movements and evaluation of muscle relaxation. The mean induction time was 4.71 min. RT1 and RT2 were significantly longer in G2. No significant differences were found in SpO2 or ƒR. HR did not vary significantly along time, but was higher in G2. Rectal temperature did not show differences between treatments, but decreased significantly with time in G2. Four of nine animals in G1 showed movements, while no animals in G2 did and muscle relaxation was determined to be better in this latter group. Both protocols were adequate for short-term field immobilization, with minimal alterations of HR and T and relatively short recovery times. Isoflurane provided better immobilization with statistically significant prolongation of recovery times.
KeywordsKetamine Dexmedetomidine Isoflurane Field immobilization Opossum
The authors wish to thank Flavia Netto, Tomas Franzese, Esteban Actis, and Yanina Berra for field assistance; Dr. Ricardo Gürtler and the Ecoepidemiology Lab for institutional assistance; and Dr. Miguel Angel Rinas and the staff of Parque Ecológico El Puma, Ministry of Ecology and Natural Resources of Misiones.
This study was performed as part of an UBACyT project, supported by the University of Buenos Aires. Other sources of founding: a grant from Roemmers Foundation (Hernán Argibay), Consejo Nacional de Investigaciones Científicas y Técnicas (PIP 2012-2015), Agencia Nacional de Promoción Científica y Tecnológica (PICT 2011-2072, PICTO-Glaxo 2011-0062) (Projects directed by Dr. Ricardo Gürtler).
Compliance with ethical standards
Conflict of interest
The authors declare that they have no conflict of interest
All procedures performed involving animals were in accordance with the ethical standards of the Institution (Veterinary Sciences School, University of Buenos Aires) and were approved by its Institutional Animal Care and Use Committee (protocol no. 2012/36).
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