Sterilization of Hybrid Galapagos Tortoises (Geochelone nigra) for Island Restoration: Part 1 Female Endoscopic Oophorectomy Under Ketamine-Medetomidine Anesthesia
American Association of Zoo Veterinarians Conference 2010
S. Emmanuelle Knafo1, DVM; Stephen J. Divers1, BVetMed, DZooMed, DACZM, DECZM (Herp), FRCVS; Samuel Rivera2, DVM, MS, DAVBP (Avian); Linda J. Cayot3, PhD; Washington Tapia Aguilera4; Joseph Flanagan5, DVM
1Department of Small Animal Medicine and Surgery, College of Veterinary Medicine, University of Georgia, Athens, GA, USA; 2Zoo Atlanta, Atlanta, GA, USA; 3Galapagos Conservancy, Fairfax, VA, USA; 4Galapagos National Park Service, Puerto Ayora, Galapagos, Ecuador; 5Houston Zoo, Inc., Houston, TX, USA


Oophorectomy has traditionally been performed through a plastron osteotomy or prefemoral coeliotomy.1,3 Plastron osteotomy is typically a longer, more traumatic and invasive procedure than a soft tissue, prefemoral approach. Prefemoral coeliotomy offers limited visualization of viscera compared to plastron osteotomy; however, an endoscope-assisted oophorectomy technique has recently been described for small species of Chelonia and offers a minimally invasive approach with improved visualization and accessibility.2 The aim of this study was to further develop the endoscopic technique to permit sterilization of giant chelonians. An endoscopic sterilization technique was developed in 15 female giant Galapagos tortoises (Geochelone nigra) as part of a conservation and ecosystem restoration project. A bilateral prefemoral approach was made and the ovaries were identified using a 5 mm x 33 cm rigid telescope. In the case of endoscope-assisted oophorectomy, the ovaries were exteriorized though the same incision, the vasculature was ligated, and the mesovarium transected. Two tortoises had immature ovaries which were unable to be exteriorized. In these animals, endoscopic oophorectomy was performed using radiosurgery. Closure of the incisions was routine. All tortoises except one recovered well from surgery. There were no reported complications 6 weeks postoperatively. These results suggest that endoscopic and endoscopic-assisted oophorectomy are safe and practical techniques to sterilize or treat reproductive disorders in large chelonian species. These techniques minimize anesthesia, surgery, and recovery times and have few postoperative complications. This study also demonstrated that the described techniques are easily accomplished either in the clinic or in a field setting and have potential applications for immature as well as sexually mature chelonians.


The authors would like to thank the Galapagos Conservancy, the Charles Darwin Foundation, the Galapagos National Park, the Pamela de Journo Fund, Karl Storz Veterinary Endoscopy America Inc., Envisionier Medical Technologies Inc., Ellman International Inc., and Continental Airlines for their support of this project.

Literature Cited

1.  Hernandez-Divers, S.J. 2004. Surgery: principles and techniques. In: Raiti, P., S. Girling, eds. Manual of Reptiles. British Small Animal Veterinary Association, Cheltenham, England. Pp. 147–167.

2.  Innis, C., S.J. Hernandez-Divers, D. Martinez-Jimenez. 2007. Coelioscopic-assisted prefemoral oophorectomy in chelonians. Journal of the American Veterinary Medical Association. 230:1049–1052.

3.  Mader, D.R., R.A. Bennett, R.S. Funk, K.T. Fitzgerald, R. Vera, S.J. Hernandez-Divers. 2006. Surgery. In: Mader, D.R., ed. Reptile Medicine and Surgery. Elsevier., St. Louis, MO. Pp. 581–630.


Speaker Information
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S. Emmanuelle Knafo, DVM
Department of Small Animal Medicine and Surgery
College of Veterinary Medicine
University of Georgia
Athens, GA, USA

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