Currently, there are only two Northern White Rhinos left in the world, with both of them (Najin & Fatu) being female. Science is the only hope for the [possible] survival of the subspecies since neither is able to carry a calf. it was discovered that Fatu has degenerative lesions in her uterus and Najin has weak hind legs which could cause complications if she fell pregnant.
This led to the start of a journey where an international consortium of scientists and conservationists last week completed a procedure that could enable assisted reproduction techniques to do just that. On August 22, 2019, a team of veterinarians successfully harvested eggs from the two females who live in Ol Pejeta Conservancy — a procedure that has never been attempted in northern white rhinos before.
The eggs will now be artificially inseminated with frozen sperm from a northern white rhino bull, and in the near future the embryo will be transferred to a southern white rhino surrogate mother. The successful procedure was a joint effort by the Leibniz Institute for Zoo and Wildlife Research (Leibniz-IZW) Berlin, Avantea, Dvůr Králové Zoo, Ol Pejeta Conservancy and the Kenya Wildlife Service (KWS).
The procedure was the result of years of research, development, adjustments and practice. “Both the technique and the equipment had to be developed entirely from scratch”, says Prof. Thomas Hildebrandt from Leibniz-IZW and Dr. David Ndeereh from the Kenya Wildlife Service (KWS), who headed the procedure. “We were able to harvest a total of 10 oocytes – 5 from Najin and 5 from Fatu – showing that both females can still provide eggs and thus help to save these magnificent creatures.”
The procedure was conducted with a probe, guided by ultrasound, which harvested immature egg cells (oocytes) from the ovaries of the animals when placed under general anaesthetic. “The anaesthesia went smoothly without any complications although these animals had not been immobilized for the last five years,” say Frank Goeritz from Leibniz-IZW, Dr. Domnic Mijele from KWS and Dr. Stephen Ngulu of Ol Pejeta.
The oocytes were immediately airlifted to a lab in Italy, where they will be fertilised with cryogenically frozen sperm. Then, scientists will have to develop a technique to transfer the embryos into a surrogate rhino.
It is a race against time for the species who don’t have much time left especially since there are many obstacles along the way which include:
- This is the first time such a procedure is being done
- The egg collection is a complicated procedure and can only be conducted three times a year, so the number of natural gametes (and therefore possible attempts) is limited.
- And second,the genetic variability is very limited because the number of individuals from which sperm and egg cells can be utilized is down to just six.
If IVF is successful, what is the long-term plan?
The long-term objective is to reintroduce northern white rhinos and future offspring into secure habitats within their former range. This objective may only be realised in 50-70 years.After foundation of a viable breeding nucleus at Ol Pejeta, new populations can be trans located to create or reinforce existing white rhino populations with northern white rhino genes. By increasing the number of populations, the overall risk to the northern white rhino will be spread and reduced.