Scientists racing against time to rescue the northern white rhino from going extinct have developed three viable embryos following a recent procedure.
On July 9, the scientists and conservationists of Leibniz Institute for Zoo and Wildlife Research (BioRescue), Safari Park Dvůr Králové, Kenya Wildlife Service, and Ol Pejeta Conservancy conducted the sixth successful oocyte collection at Ol Pejeta.
During the procedure, 17 eggs were collected from Fatu and immediately airlifted to Avantea laboratory in Cremona, Italy for maturation, fertilisation, embryo development, and cryopreservation.
In addition, the specialists at Avantea managed to find viable sperm from Angalifu, a northern white rhino bull who lived in San Diego and died in 2014, to develop one of the three embryos.
Previously, Suni has contributed all the semen samples needed as it was thought that Anagalifu’s sperm was incapable of successfully fertilising the eggs.
Using the sperm of a completely unrelated rhino has diversified the genetic pool of the cryo-preserved embryo population.
“A total of 12 pure northern white rhino embryos are now preserved awaiting future implantation into southern white rhino surrogate(s),” the scientists said.
The BioRescue mission will continue to collect oocytes every three to four months, in order to create further embryos, as long as the Covid-19 pandemic allows the team to travel to Ol Pejeta.
In a discussion prior to the ovum pick-up on July 9, the team of scientists and conservationists decided not to perform an oocyte collection on Nájin, the older of the two northern white rhino females.
Her future role in the scientific programme will be discussed in the coming weeks from an ethical perspective, and a science-backed decision will be announced.
“So far, none of Nájin’s eggs have been of sufficient quality to turn into viable embryos. All 12 embryos produced so far used oocytes from Nájin’s daughter, Fatu.”
“During the recent procedures, it was clear that Nájin’s ovaries are no longer producing a large number of eggs and that their quality is compromised. She is an old lady, and it seems it’s not worth subjecting her to the stress of any further procedures. However, her health status will be frequently monitored.” said Jan Stejskal, Director of International Projects at Safari Park Dvůr Králové.
Regardless of the decision that will be made, Najin still has an important role to play as an ambassador for the plight of her species and as a future mentor once we have a calf/ calves born.
The next step in the BioRescue plan to save the northern white rhinos is to implant a pure northern white rhino embryo into a southern white rhino surrogate.
The team will need to observe the potential surrogates to determine the ideal time for implantation to achieve this.
In line with this, Ol Pejeta and the KWS translocated two southern white rhino females, Arimiet and Mojo, to the sterilised teaser bull, Owuan’s enclosure.
This process took two days on July 20 and 21, 2021.
The process of translocation is delicate.
It requires absolute precision and care performed by a team of veterinarians and rangers to ensure its success.
Rhinos roam freely in Ol Pejeta and are typically found deep in the bush.
In carrying out this process, the teams had to walk miles through the thick bush to find Arimiet and Mojo.
Once found, and while keeping a safe distance, each rhino was darted.
The teams then quickly followed the rhinos further into the bushes to ensure that they did not get hurt when the sedative kicked in.
Using a sedative is crucial as it makes it safe and easier to get the capture truck as close as possible to the rhinos and consequently quickly guide them into the truck when the sedative starts wearing off.
The capture truck is specially adapted to translocate rhinos safely and securely.
This time, however, one of the rhinos was not happy about the disruption. As soon as it was let free, it made a run for the team.
The translocation team had to run almost five kilometres to get out of harm’s way, and fortunately, no one was injured.
Arimiet is 19 years old and Mojo is eleven years old.
Their selection to become potential surrogates was based on their previous reproduction records, the number of calves she had had, mothering skills, and age difference.
Arimiet and Mojo have both had a successful calving history making them the ideal candidates to receive the first embryos and contribute towards saving a species.
The age difference enables there to be a balance in interaction with Owuan, the bull.
Arimiet and Mojo have settled in well into their new area and are showing positive signs of interaction with Owuan. BY THE STAR