Dipartimento di Scienze Veterinarie, Università degli Studi di Torino, Largo Paolo Braccini 2, 10095 Grugliasco, Torino, Italy.
J Wildl Dis. 2021 Jul 1;57(3):495-502. doi: 10.7589/JWD-D-20-00174.
The nutria (Myocastor coypus), a rodent native to South America, has been introduced and has established feral populations at numerous locations in North America, Europe, and Asia. As such, the nutria is subject to research and management programs, including investigation of surgical fertility-control techniques. We evaluated the efficacy of a mixture of ketamine and medetomidine, with additional use of isoflurane and reversal with atipamezole, to provide safe, reliable anesthesia for surgical procedures under field conditions. We anesthetized 40 free-ranging nutrias between December 2018 and March 2019, in Turin, Italy, to perform surgical reproduction control techniques. We administered a ketamine and medetomidine mixture (6 mg/kg and 140 µg/kg, respectively) after trapping the animals and weighing them in the cage traps. After induction, we reweighed the rodents and performed a brief clinical examination. The times of loss of palpebral and pedal reflexes were noted. After induction of anesthesia, heart rate, respiratory rate, and percentage of oxygen saturation were monitored and recorded. Isoflurane was delivered through a face mask to 27 nutrias (70%) to maintain an adequate depth of anesthesia. Upon completion of surgery and other procedures, atipamezole was administered to the animals at doses 2.5 higher than those of medetomidine (actual dose: 366±31 µg/kg). Induction times were short (3±2 min), with the animals completely immobilized. The heart rate and respiratory rate both decreased. After administration of atipamezole, recoveries were smooth and complete. There were two deaths after higher doses of atipamezole and longer surgeries. Carprofen (4 mg/kg) was administered subcutaneously for its analgesic effects. The animals were released at the end of all the procedures. Overall, the medetomidine and ketamine mixture, with supplemental isoflurane in most instances, provided a reliable anesthesia in free-ranging nutrias, adequate for performing surgical procedures under field conditions.
海狸鼠（Myocastor coypus）原产于南美洲，现已被引入并在北美洲、欧洲和亚洲的许多地方建立了野生种群。因此，海狸鼠受到了研究和管理计划的关注，包括对手术生育控制技术的调查。我们评估了氯胺酮和甲磺酸右美托咪定混合物的效果，额外使用异氟烷，并使用阿替美唑逆转，以在野外条件下为手术提供安全、可靠的麻醉。我们于 2018 年 12 月至 2019 年 3 月在意大利都灵对 40 只自由放养的海狸鼠进行了麻醉，以进行手术繁殖控制技术。我们在将动物困在笼中并称重后，给它们注射了氯胺酮和甲磺酸右美托咪定混合物（分别为 6 毫克/千克和 140 微克/千克）。诱导后，我们重新称重啮齿动物并进行了简短的临床检查。记录了失去眼睑和跖反射的时间。麻醉诱导后，通过面罩监测和记录心率、呼吸频率和氧气饱和度百分比。给 27 只（70%）海狸鼠使用异氟烷来维持足够的麻醉深度。手术和其他程序完成后，给动物注射比甲磺酸右美托咪定高 2.5 倍的阿替美唑（实际剂量：366±31 微克/千克）。诱导时间很短（3±2 分钟），动物完全固定。心率和呼吸频率均下降。给予阿替美唑后，恢复平稳且完全。在给予较高剂量的阿替美唑和较长时间的手术后，有两只死亡。皮下注射卡洛芬（4 毫克/千克）以缓解疼痛。所有程序结束后，动物被释放。总体而言，在大多数情况下，补充异氟烷的甲磺酸右美托咪定和氯胺酮混合物为自由放养的海狸鼠提供了可靠的麻醉，足以在野外条件下进行手术。
