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Introduction
The desert tortoise (Gopherus agassizii ) occurs over large portions of the Mojave and Sonoran Deserts in the southwestern USA and northwestern Mexico. It was designated as threatened under the US Endangered Species Act 1973.
Abandoned and relinquished 'pet' tortoises, uncontrolled backyard breeding of 'pets' and displacement from urban development have resulted in thousands of animals received by the Desert Tortoise Conservation Center (DTCC) in Las Vegas, Nevada. While most of Nevada desert tortoises are experimentally relocated to appropriate and controlled habitat within the state, an urgent solution to this critical problem is required. This paper reports a study to evaluate endosurgical sterilisation in this species with the goal of decreasing backyard reproduction.
Orchiectomy in chelonians is a challenging procedure since the testes are located in the dorsocaudal coelomic cavity, intimately associated with the kidney, below the carapace. The mesorchium of chelonians is short and tight, such that the testes cannot be exteriorised from the coelom (O'Malley 2005, Innis and others 2013). Other sterilisation techniques such as phallectomy, orchiectomy via plastron osteotomy or prefemoral orchiectomies without coelioscopy have been performed in male chelonians, but all have disadvantages (Lawson and Garstka 1985, Licht and others 1985, Rivera and others 2011, Innis and others 2013). In contrast, prefemoral orchiectomy with the aid of coelioscopy offers a minimally invasive approach and has been shown to be effective, safe and appears to be a preferable method for sterilisation of male freshwater turtles because of improved surgical visualisation and accessibility, combined with shorter healing and recovery times (Innis and others 2013).
The previously reported coelioscopic orchiectomy technique was accomplished by a single vascular clip or monopolar radiosurgery across a short mesorchium (Innis and others 2013). Different species have variable testicular anatomy, as well as seasonal and age-related testicular variations (Innis and others 2013). Consequently, the removal of larger testes in larger species would be more problematic, requiring additional internal dissection. For example, an attempt at coelioscopic orchiectomy of a hybrid Galapagos tortoise (Geochelone nigra ) was reported to have failed (Rivera and others 2011). The purpose of this study was to develop a feasible and effective method of endoscopic orchiectomy to be used in larger species, using the desert tortoise as a model. We describe an...