Cheetah Assisted Reproduction Takes a Giant Step Forward at Wildlife Safari
Editor's note: The following press release comes from Wildlife Safari in Oregon, where Dr. Autumn Davidson, a specialist in reproductive issues, and Tomas Baker collaborated on a new method to help preserve the endangered cheetah. Davidson and Baker, based at the William R. Pritchard Veterinary Medical Teaching Hospital, have traveled to Namibia, China, and Madagascar to assist scientists working on reproduction and other health concerns in endangered species.
Winston, OR – October 1, 2008 – Excitement and expectations ran high at Wildlife Safari during the week of September 21, when for the first time in history two momentous advances were made that could have a significant impact on reproduction in captive cheetahs. Drs. Adrienne Crosier and Pierre Comizzoli of the Smithsonian’s National Zoo conducted the first ever study on carnivores that involves collecting mature egg cells from older female cheetahs, fertilizing them and later transferring the embryos into younger surrogate cheetahs. Another huge step was taken when Dr. Autumn Davidson of UC Davis School of Veterinary Medicine refined a non-surgical method of artificial insemination (AI) in cheetahs. Researchers and the veterinary and cheetah staff of Wildlife Safari were thrilled to work together to make these successful breakthroughs in cheetah assisted reproduction.
With fewer than 15,000 cheetahs surviving in the wild, and approximately 1,400 captive cheetahs in the world, scientists and managers have struggled to save the cheetah from extinction. Breeding cheetahs in captivity has been notoriously difficult--it has taken years to determine the special needs that cheetahs have and just a few zoos have been successful*. And with just around 25% of cheetah females reproducing, the captive population is not self-sustaining. New and innovative scientific methods, such as semen collection and cryopreservation (freezing at very low temperatures), artificial insemination and in vitro (test tube) fertilization, have been developed to help reverse the decline of wild and captive populations.
In the 1990s, Dr. JoGayle Howard and scientists from the National Zoo devised a new method of artificial insemination in felids (the cat family). This procedure involves making a small surgical incision in the abdomen and a laparoscope inserted to locate the uterus. Previously frozen or fresh cheetah sperm is then infused directly into the uterus. As a result of this procedure, there have been nineteen cubs born in the US. The success rate of this procedure using freshly collected sperm is ~45% and with frozen/thawed sperm is ~22%.
In the last two years, Dr. Davidson also has been attempting to refine the process of a non-surgical trans-cervical AI whereby a small tube (catheter) is passed through the cervix and the semen can be infused directly into the uterus. Although this trans-cervical method has been used successfully on humans, dogs and cats, the anatomy and hormonal makeup of cheetahs have presented numerous challenges. Success finally took place on September 24, 2008 at Wildlife Safari. The right combination and size of endoscope and catheter was found to allow a successful pass through the cervix of three different cheetahs. In the future this new procedure will make it possible to infuse sperm and potentially transfer embryos.
The team also collected sperm from one of our males, Hulets, and used the laparoscopic method to artificially inseminate a nine-year-old cheetah named Mopane. The hope is that Mopane will give birth in about three months, thereby furthering the preservation of this elegant cat.
Of additional importance, the National Zoo researchers conducted the first studies at Wildlife Safari to test the viability of mature egg cells (oocytes) of older female cheetahs. For unknown reasons, reproduction declines in cheetahs around eight years of age. The study is the first in any carnivore to compare the egg quality with the age of the female. To begin the study, ultrasonographic evaluation of three of the park’s older female cheetah’s reproductive organs were performed by Tomas Baker of UC Davis School of Veterinary Medicine. Drs. Crosier and Comizzoli then used the laparoscopic method to harvest the mature eggs. While the donors may not be able to establish pregnancies, the eggs from these cheetahs may possibly be fertilized and developed in vitro and later be implanted in younger females. This research will help to enhance reproduction and improve genetic management of the captive cheetah population.
*Wildlife Safari is a 600-acre drive-through game park located in Winston, Oregon. The park has a long history of conservation and research and is home to a well-established cheetah reproduction program. Since 1973, there have been 161 cubs born at the park, including 11 cubs born in 2007, making Wildlife Safari the most successful cheetah breeding facility in the western hemisphere. The park is proud of their cheetah program and was privileged to have the Smithsonian’s National Zoo and UC Davis team include them in their cheetah reproductive studies.
For additional information on the Cheetah Department at Wildlife Safari, contact:
Dan Brands, General Curator
P.O. Box 1600
Winston, OR, 97496
(541) 679-6761, ext.201, firstname.lastname@example.org