Scientists achieve world’s first rhino embryo transfer
There are only two living northern white rhinoceros.
Scientists and conservationists in Kenya have succeeded in achieving the world’s first pregnancy of a rhinoceros through embryo transfer.
The success of this embryo transfer and pregnancy could help scientists to save the critically endangered northern white rhinoceros, of which there are only two living specimens, from extinction.
Scientists and veterinary surgeons from BioRescue, led by the Leibniz Institute for Zoo and Wildlife Research, chose Curra, a southern white rhinoceros living in the Ol Pejeta Conservancy in Kenya, to act as the surrogate mother for this embryo transfer.
The embryos were produced using oocytes retrieved from Elenore, a southern white rhinoceros that lives in Pairi Daiza Zoo in Belgium. They were then fertilised using sperm from another southern white rhino, Athos, living in Zoo Salzburg in Austria.
The oocytes were fertilised in vitro by intracytoplasmic sperm injection, and developed into blastocysts at Avantea’s laboratories in Italy.
When Ouwan, a vasectomised teaser male rhino, mated with Curra, it indicated that it was ideal timing for the embryo transfer on 24 September. Scientists transferred two embryos, to increase the chance of pregnancy.
After the procedure, Curra was closely monitored within her enclosure at the conservancy. Ouwan showed no further interest in Curra, which suggested that the transfer had resulted in a pregnancy.
However, before the team could perform a pregnancy check on Curra in November, Ouwan was found dead. Three days later, Curra was also found to have died.
It was discovered that extremely heavy rains had caused the surrogate enclosure to flood, setting free dormant clostridian bacteria spores. Dissections later revealed that the rhinos had developed severe systemic infections from clostridian bacterial strain, and a resultant intoxication from the bacterial toxin.
The dissections also revealed that Curra had become pregnant from the embryo transfer, and had been carrying a 70-day-old male foetus that was 6.4cm long.
The proof of concept of this southern white rhino embryo transfer could help the scientists perform a similar procedure to save the critically endangered northern rhinoceros.
Although there are only two living northern rhinos, Najin and her daughter Fatu, there are also living cells from 12 different northern rhinos stored in liquid nitrogen. The BioRescue team has produced and cryopreserved 30 northern white rhino embryos for transfer.
These embryos could be transferred into a southern white rhinoceros surrogate, potentially leading to a new generation of northern white rhinoceros.
Jan Stejskal, BioRescue project co-ordinator, said: “Our current success also shows the great potential that zoos have in saving endangered species, as all the embryos that led to this success have been produced thanks to the extensive collaboration of European zoos.
“When we as scientists and zoo experts work together with conservationists in the field, we are much more powerful than when we work separately."
Image © Shutterstock
BSAVA is to partner with BVA Live (11-12 June 2026) to champion clinical research.
