Breakthrough in Cheetah Reproductive Research
The following press release was distributed September 8 by the Cheetah Conservation Fund.
Otjiwarongo, Namibia - The first ever in vitro cheetah embryos that have developed to the blastocyst stage have been produced at the Cheetah Conservation Fund (CCF) in collaboration with the Smithsonian Institution and the University of California, Davis, School of Veterinary Medicine.
The eggs were recovered from some of CCF's captive cheetahs, and inseminated with sperm in vitro (in the lab). During this procedure new culture systems were implemented to optimize embryo development. Embryos were assessed and the first ever cheetah embryo to reach the blastocyst stage was frozen for storage in the Cheetah Conservation Fund's Genome Resource Bank, a reservoir of frozen genetic and biological materials. The oocytes (eggs) used to produce these historical embryos were collected from Nestlé and Hershey --two of CCF's resident non-releasable cheetahs, of which four blastocysts from Nestlé were frozen. What makes this even more exciting is that the sperm used were collected over a year ago from a CCF's resident male, Cruise, and had been frozen and stored in the Genome Resource Bank. This proves that the techniques researched at CCF to freeze and thaw cheetah sperm are viable.
Last year another major breakthrough was made when the timing of aspiration (collection) of oocytes was established at 28 to 30 hours post hormone treatment. Building on what was discovered last year, scientists were able to take this research to the next level with the help of the captive cheetahs living at CCF, as a large enough sample size was needed in order to test different incubation conditions needed by embryos to develop successfully. All these methods have been established using domestic cats as models, but need to be adapted for each wild carnivore species.
While in vitro fertilisation is relatively routine in many other species, including humans, carnivores have proven to be a challenge when it comes to assisted reproduction and pioneering methodologies need to be developed. In order to successfully grow cheetah embryos in vitro, the correct temperature, CO2 and growth mediums needed to be established that are very specific to cheetah embryos. Dr. Pierre Comizzoli, a veterinary reproductive physiologist from the Smithsonian Institution's National Zoo has been studying in vitro processes in antelope and carnivores for over 14 years. Dr. Comizzoli said, "This ground-breaking research has been made possible by the long-term collaboration between the Smithsonian and CCF, which has proven invaluable for the conservation of this unique species."
Dr. Adrienne Crosier, a reproductive physiologist from the Smithsonian Institution's National Zoo, and team leader said, "Typically, cheetahs reproduce poorly in captivity and the efficiency of reproduction for female cheetahs drops after about 8 years of age. This research, initiated in December 2005, is the first of its kind on any of the non-domestic carnivore species and is evaluating the physiology of the influence of age on cheetah reproduction. Understanding how oocyte quality and uterine morphology and anatomy are affected by age are vital to improving assisted reproductive techniques for the cheetah." Dr. Autumn Davidson, veterinarian and reproductive specialist and Tom Baker, a specialist in ultra-sound technology, both from the University of California, Davis, School of Veterinary Medicine, used ultrasound technology to investigate the morphology of female cheetah reproductive tracts.
This study includes 33 cheetahs from seven facilities in two countries. Information gathered will conclude a long-term project investigating reproductive health in older female cheetahs and documenting reproductive senescence in these felids. Dr. Laurie Marker, CCF's Executive Director, said, "This breakthrough in cheetah reproductive research has far-reaching implications for the conservation of cheetah and demonstrates the benefits of an integrated approach of both captive and wild cheetah conservation programmes to ensure the survival of the species."
Dr. Autumn Davidson, a faculty member at the William R. Pritchard Veterinary Medical Teaching Hospital, is a small animal internal medicine veterinarian specializing in reproductive issues. Her expertise in the use of endoscopy to examine and diagnose internal problems has taken her to China, Namibia and Madagascar for projects related to reproduction in and conservation of lemurs, giant pandas and cheetahs.
Tomás Baker, MS, manages the small animal Ultrasound Service of the William R. Pritchard Veterinary Medical Teaching Hospital. Working with Dr. Autumn Davidson and using specialized equipment for the examination of internal structures in a variety of animals, he has participated in international projects relating to lemurs, giant pandas, and cheetahs. He has trained technicians in other countries in the use of modern ultrasound technology, taking portable ultrasound equipment through many an airport on visits to China, Namibia and Madagascar.
The Cheetah Conservation Fund is a Namibian non-profit trust dedicated to the long-term survival of the cheetah and its ecosystems. Since 1990, the organisation has developed education and conservation programmes based on its bio-medical cheetah research studies and published scientific research papers. Its educational programmes are reaching more than 140,000 outreach school learners and 500 farmers. The Fund has donated more than 260 Anatolian livestock guarding dogs to commercial and communal farmers as part of the CCF innovative non-lethal livestock management programme and has established a cheetah genome resource bank of cheetah tissue and blood and sperm samples.
Research into cheetah biology and ecology has greatly increased our understanding of the fastest land animal and education programmes for schools and the farming community help change public attitudes to allow predator and humans to co-exist. However, despite the many successes of CCF programmes, the cheetah is still Africa's most endangered big cat. The captive cheetah population is approximately 10% of the world's remaining cheetah population with about 1400 cheetahs in about 247 zoological institutions in about 49 countries throughout the world. Annually there are about 160 cubs born with approximately a 23% infant mortality. A female cheetah can have from one to eight cubs born after a 93-95 day gestation with an average litter of 4-5. Dr. Laurie Marker is the International Cheetah Studbook Keeper and registers all cheetahs living in captivity in the world.