CASE REPORT Anesthetic management of a white rhinoceros (Ceratotherium simum) undergoing an emergency exploratory celiotomy for colic Alexander Valverde*, Graham J Crawshaw , Nicola Cribb*, Maria Bellei*, Giacomo Gianotti*, Luis Arroyo*, Judith Koenig*, Maya Kummrow*, & Maria Carolina Costa* *Department of Clinical Studies, Ontario Veterinary College, University of Guelph, Guelph, ON, Canada  Toronto Zoo, Scarborough, ON, Canada Correspondence: Alexander Valverde, Department of Clinical Studies, Ontario Veterinary College, University of Guelph, Guelph, ON, Canada N1G 2W1. E-mail: valverde@uoguelph.ca Abstract Observations A 26-year-old male white rhinoceros (Ceratotherium simum), weighing approximately 2000 kg was anesthetized for an exploratory celi- otomy. Sedation was achieved with intramuscular butorphanol (0.04 mg kg )1 ) and detomidine (0.025 mg kg )1 ) and induction of anesthesia with intravenous glyceryl guaiacolate (50 g) and three intravenous boluses of ketamine (200 mg, each); the trachea was then intubated and anesthesia maintained with isoflurane in oxygen using a circle breathing system. Positioning in dorsal recumbency for the surgery and later in sternal recumbency for the recovery represented challenges that added to the prolonged anesthesia time and surgical approach to partially correct an impaction. The rhinoceros recovered uneventfully after 10.4 hours of recumbency. Conclusions Anesthetic management for an explor- atory celiotomy with a midline approach is possible in rhinoceroses, although planning and extensive staff support is necessary to adequately position the patient. Keywords butorphanol, colic, detomidine, hypercap- nia, hypoxemia, isoflurane, rhinoceros. Introduction General anesthesia of rhinoceroses is becoming more frequent for a variety of elective or emergency procedures (Cornick-Seahorn et al. 1995; Steg- mann et al. 2001; Atkinson et al. 2002; Bush et al. 2004; Adams et al. 2005; Esson et al. 2006; Portas et al. 2006; Goodman et al. 2007). The white rhi- noceros is listed as ‘Near threatened’ in the Red List of Threatened Species of the International Union for Conservation of Nature (IUCN 2008). Worldwide there is a collection of 730 white rhinoceroses in captivity of which 196 are in North America at 56 institutions (Foose & Wiese 2006; WAZA 2008); therefore important efforts are directed at preserving all specimens in captivity and in the wild. Due to their size and behavior, anesthetic man- agement of rhinoceroses is challenging and ade- quate planning is necessary to minimize risk. Injectable anesthetic techniques are more frequently used than inhalant anesthesia since most proce- dures are short and performed under field conditions (Simons & Jenke 1977; Hattingh et al. 1994; Radcliffe et al. 2000; Stegmann et al. 2001; Atkin- son et al. 2002; Bertelsen et al. 2004; Adams et al. 2005; Esson et al. 2006; Goodman et al. 2007; Radcliffe & Morkel 2007). However for longer recumbency times or more invasive surgical 280 Veterinary Anaesthesia and Analgesia, 2010, 37, 280–285 doi:10.1111/j.1467-2995.2010.00534.x