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World’s oldest white rhinos take retirement from breeding program

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One of the world’s remaining two northern white rhinos has been retired from a breeding program aimed at saving the species from extinction.

The decision to discontinue harvesting Najin’s ( One of the world’s last northern white rhinos) eggs was made after an “ethical risk assessment” that took her age and other variables into account. 

Najin and her daughter Fatu are both incapable of carrying a rhino calf to term. 

Although the species’ final male died in 2018, his sperm was recovered and used to fertilize eggs.

The process

A team of veterinarians extracts the rhino’s eggs using techniques established over many years of research. The eggs are then fertilized in an Italian lab with sperm from two deceased males. 

So far, scientists have generated 12 embryos, which they intend to implant into surrogate moms chosen from a herd of southern white rhinos.

Bio Rescue

The scientific group in charge of the project, BioRescue, said it assessed many hazards before deciding to cease harvesting Najin’s eggs.

northern white rhino

“Retiring one individual from a conservation program because of animal welfare considerations is usually not a question to think about for long… but when one individual is 50 percent of your population, you consider this decision several times,” said head veterinarians Frank Göritz and Stephen Ngulu.

Ultrasound exams indicated multiple small, benign tumors on Najin’s cervix and uterus, as well as a cyst on her left ovary, despite her old age. 

rescue, on the other hand, stated that she will continue to participate in the plan in other ways, such as supplying tissue samples for stem cell research.

It’s hoped she can also “transfer her social knowledge and behavior” to future offspring.

Brink of extinction

Poaching and habitat destruction have pushed northern white rhinos to the verge of extinction. 

Najin was born in a Czech zoo but relocated to Kenya’s Ol Pejeta Conservancy a decade later, where she has been living under armed guard.

New northern white rhinos embryos, new hope for other rhinos species

The fragile promise of a new life flickered into existence in early July. Not on a normal microscope slide, but a clean microscope slide in a sterile facility in Cremona, Italy, thousands of kilometers away from the creature’s ancestral homeland in Sub-Saharan Africa. Shortly after, lab technicians submerged it in liquid nitrogen, rapidly cooling it to 196° Celsius (-321° Fahrenheit) to stop the creature’s development.

The embryo, one of three generated this spring, is barely a few cells in size, but it signals hope for the nearly extinct northern white rhinoceros.

The embryos were created in July by BioRescue, a consortium made up of the Leibniz Institute for Zoo and Wildlife Research (Leibniz-IZW) in Germany, Safari Park Dvr Králové in the Czech Republic, the Kenya Wildlife Service, and the Ol Pejeta Conservancy in Kenya, bringing the total number of northern white rhino embryos to 12. The news is a big victory for the subspecies, which now has only two members: a mother and daughter pair who are both incapable of bearing a calf.

One of the embryos was made with genetic material from a male rhino named Angalifu, whose sperm was previously thought to be too low in quality to generate healthy children, giving important genetic diversity to the embryo pool. To date, all additional embryos have been generated with sperm from Suni, a northern white rhino bull. 

Some scientists feel that the technologies pioneered by BioRescue and other organizations could provide hope not only for the northern white rhino but also for other rhino species. Others believe that our desperate efforts indicate that we have already failed.

the rescue has devised an audacious plan: implant northern white rhino embryos into females of the southern white rhino (Ceratotherium simum simum), a closely similar subspecies with the same gestational period as its northern counterpart. Calf development should, in theory, follow a similar pattern, allowing scientists to defy nature and generate children from subspecies with no reproductively viable females.

The only two northern white rhinos on the earth, Najin, and Fatu are held at Ol Pejeta Conservancy in Kenya, where they were relocated from the Dvr Králové zoo in 2009. Every three to four months, scientists collect their eggs and fly them to the Avantea lab in Cremona, where they are processed and stored. Due to her age and the state of her remaining eggs, researchers chose not to harvest eggs from Najin, the elder of the two rhinos, in the most recent cycle.



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