Laparoscopic Reproductive Sterilization as a Method of Population Control in Free-Ranging African Elephants (Loxodonta africana)
In many areas of southern Africa, elephant populations have outgrown the carrying capacity of parks and reserves. Elephant populations in certain wildlife parks have caused dramatic changes to the natural flora and fauna and have forced wildlife officials in several locations to consider elephant culling. Ecosystem destruction by elephants and the animal welfare concerns around culling are two of the most significant conservation issues facing Africa. Wildlife officials are urgently seeking effective and humane methods of population control in elephants.
Laparoscopic surgery provides a direct view of internal organs and allows tissue manipulation via a minimally invasive procedure utilizing relatively small incisions. Recent advances in medical technology have made laparoscopic surgery a reality in very large animals, even in free-ranging situations.
In July 2004, an international team of veterinarians, technicians and wildlife officials performed the first-ever, hand-assisted laparoscopic sterilization of free-ranging female elephants. Animals were anesthetized via remote injection using a combination of etorphine and azaperone. The elephants were positioned in lateral recumbency and the skin was surgically prepared for laparoscopy. An approximately 35-cm incision was made in the paralumbar fossa, just caudal to the last rib. The surgeon’s arm was introduced into the abdomen and manual palpation was used to identify the ovary and place a snare around the pedicle. A 12-cm internal diameter plastic tube was placed through the incision into the abdomen and positioned so that the snare and ovary were inside the tube. This tube served as a working port for easier access to the ovary and helped protect other visceral organs from trauma. An equine laparoscope (57 cm, 0 degree) was placed inside the tube and used to visualize the ovary. The ovarian pedicle was ligated utilizing 18-gauge stainless steel cerclage wire. Two wire ligatures were twisted around the base of each ovarian pedicle using an electric drill. The peritoneum, muscle layers and subcutaneous layers were each closed with #2 PDS. The skin was closed using stainless steel suture in a modified far-far-near-near pattern, which incorporated stents. Once the procedure was complete on each side, the animals were rolled to the contralateral side for the same procedure.
During surgery, the elephants were fitted with telemetry collars for postoperative monitoring. VHS and GPS tracking technology were utilized for 10 mo after surgery to monitor and track the elephants after surgery. The incisions healed without complication, and ongoing direct observation of the animals and the herds have demonstrated no adverse social or behavioral issues since the surgical sterilization. A follow-up examination of the elephants is scheduled for June 2005, including a complete health assessment, evaluation of the surgical sites, ultrasonography of the reproductive tract and blood collection for complete blood count, serum chemistry and endocrinology profiles.
Male elephants have intra-abdominal testes, and thus surgical sterilization requires abdominal surgery. In an attempt to improve our elephant laparoscopy technique, a crane is now utilized to support the anesthetized elephant in a standing position, which allows for abdominal insufflation and improved laparoscopic visualization. Using this positioning technique, it is possible to perform reproductive sterilization procedures completely laparoscopically. This, in turn, allows for a much smaller incision, reduced surgical/anesthetic times, and a more rapid postoperative healing time. In males, a 10-cm incision is made just cranial to the tuber coxae. A cannula and 90-cm laparoscope with an operating channel are placed into the abdomen. Insufflation is employed and the testes are identified hanging from the dorsal body wall in the mesorchium. A modified epididymectomy/vasectomy is performed by resecting a 4-cm portion of the deferent ducts. The peritoneum and subcutaneous tissues are closed using #2 PDS, and skin closed with simple horizontal mattress pattern and #2 nylon.
The initial investigation into sterilization of bull elephants began in February 2005, and the first in situ surgeries are scheduled for June 2005. The bull elephants will be fitted with telemetry collars and monitored for 10 mo postoperatively.
Minimally invasive laparoscopic surgery allows patients to rapidly return to full function and can be utilized in free-ranging elephants with minimal disturbance to the animals or the herd. In certain situations, surgical sterilization of free-ranging elephants may be a useful tool to wildlife officials who are currently faced with ecosystem health concerns and animal welfare issues.
We are indebted to Karl Storz Veterinary Endoscopy and to the Conservation Company of Africa for their assistance and partnership in this work. We would also like to acknowledge Li-Ann Small and J.J. Van Altena for their help and assistance with this project.