A rare Poitou donkey that lived at the Franklin Park Zoo in Boston has died.

The 15-year-old named Vollavon, who came to the zoo in 2016, was in intensive care due to several serious illnesses, including a severe stomach ulcer and laminitis, a painful inflammation of the tissue in the hoof, staff said in a statement.

According to zoo staff, her health deteriorated rapidly over the weekend and treatments were not responding well. Given the poor prognosis for her quality of life, it was ultimately decided to humanely euthanize her.

Staff said Vollavon’s death is all the more painful because it came just weeks after the birth of her foal on August 8 – the first successful birth of this rare heritage horse breed at the Franklin Park Zoo.

The young male foal was born late with some help from the veterinary staff and supported the slowly progressing birth.

Staff say the woolly boy continues to grow as his devoted animal care team feeds him milk and offers him grain and hay around the clock.

Betty, a Morgan horse, keeps the foal company in the stable and pen they share behind the scenes, staff said, adding that the foal’s growth and development are being closely monitored.

“It is always heartbreaking to lose an animal we care deeply about, but it is even more heartbreaking to lose a member of a species, or in this case breed, that Zoo New England has worked so hard to protect,” said John Linehan, president and CEO of Zoo New England, in a statement. “But despite the devastating loss of Vollavon, there is a glimmer of hope with the arrival of her young foal. We look forward to introducing him to guests at a later date. And in the meantime, visitors can continue to learn about and appreciate this unique ancient breed when they see his charismatic father, nearly five-year-old Inspector Maigret, at our Children’s Zoo.”

According to the zoo, ancient breeds such as the Poitou donkey were common on farms 100 years ago. But today many of these farm animals are threatened with extinction. Poitou donkeys, a breed bred in the Poitou region of France, are known for their large size, large ears and shaggy coat.

The breed nearly became extinct after World War II, when motorized vehicles took over and demand for mules plummeted, the zoo said. There are only about 2,500 purebred Poitou donkeys left in the world, and Franklin Park Zoo is part of a global effort to preserve the breed.