One of the world’s last two northern white rhinos has been retired from the breeding scheme that was trying to save the species from extinction. The decision to stop the scheme was taken keeping in mind her age and other factors. Neither Najin, the 32-year-old rhino, nor her daughter fatu were able to carry a rhino calf to term.

The decision to stop harvesting 32-year-old Najin’s eggs followed an “ethical risk assessment”, BBC reported.

While the last male of the species died in 2018, the sperm that was collected has been used to fertilise eggs.

The group that was leading the scheme, BioRescue, said that it had considered several risks before the decision to taken to stop harvesting Najin’s eggs.

“Retiring one individual from a conservation programme 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.

Keeping her advanced age aside, ultrasound scans showed multiple small, benign tumours on Najin’s cervix and uterus, and a cyst on her left ovary.

Even though she will not be a part of the breeding program, she will remain part of other schemes such as providing tissue samples for stem cell research.

It’s expected that she can also “transfer her social knowledge and behaviour” to future offspring.

Northern white rhinos were brought to the brink of extinction due to poaching and loss of habitat.

Najin was born in a Czech zoo. However, was moved a decade later to Ol Pejeta Conservancy in Kenya. Here, she has been living under armed protection.

White rhinos are made of two subspecies: Northern white rhinos and southern white rhinos. Nicknamed ‘square-lipped rhinos’, they have been living under armed protection in Kenya. While the population of Northern rhinos is just 2, the estimated population of the southern rhinos are around 20,000.