Melbourne Zoo's elephant calf Willow had endured a lot of pain and had gained a reputation as a fighter in her short life, but it was only on Monday that her keepers realised the "sweet, adorable little thing" was not going to make it.
The six-week-old calf had been battling a blood-borne infection for a fortnight and was showing signs of improvement, but over the weekend her condition worsened.
The zoo's head vet, Michael Lynch, said he could tell the animal had been in pain.
Her knees had swollen up – an ominous sign the staphylococcus infection had penetrated the bones in her legs – and on Monday night she was taken to the University of Melbourne's Werribee vet clinic for a CT scan, which confirmed her vets' worst fears.
"The damage to one joint of her hind leg was so severe she could not have had a normal life afterwards, even if we had been able to get the infection under control," Dr Lynch said.
"We decided not to persevere."
It was at that point that he made the difficult decision to withdraw the medical treatment a team of vets, nurses and specialists had been providing for Willow around the clock for almost seven weeks.
From the hospital, the head of the elephant enclosure, Dominic Moss, called all 18 of her vets, keepers and nurses to tell them the bad news.
All 18 gave up their Monday night and returned to the zoo to say goodbye.
The calf was gently ushered into the elephant barn and reunited with her mother Num-Oi for the last time.
While the calf was nestled beside its mother, the specialists unhooked the two intravenous drips that had been providing Willow with nutrients for most of its life.
Then they administered the injection that would put the 108 kilogram animal to sleep.
"Num-Oi stood over Willow and on two occasions slept alongside the calf," Mr Moss said.
"She was very calm – she was aware of what had happened. You could see she was sad and she has distanced herself from the rest of the herd today."
It is the second time Num-Oi, an Asian elephant, has mourned a dead calf.
Willow's brother, Sanook, died in an accident in 2013 at the age of 11 months while playing with a hanging tyre in the barn one evening.
Willow was born on June 15 with congenital carpal flexure, a condition that meant she could not stand up or suckle her mother, and was in a critical condition for her entire life.
Because of her difficulties with feeding, she struggled to get the nutrients she needed, and she was given milk formula and hooked up to a drip that provided her with protein and vital sugars.
She was cared for around the clock by a team of 18 that included an equine surgery and medicine specialist, an equine physiotherapist, a corrective farrier, a veterinary ophthalmologist, a cardiologist and a pathologist.
Corrective surgery allowed the calf to stand for brief periods, but shortly after she made it to the one-month mark she suffered a major setback.
"Just when we were getting on top of that she got the infection," Dr Lynch said.
He said Willow had been gaining weight before the infection struck.
When asked why the zoo had persisted with the round-the-clock care, Dr Lynch said he felt they had to if there was a chance to help the "critical endangered" species of elephant.
"While we felt there was a chance, we put the resources in and the zoo made that commitment," he said.
"This animal was 22 months in the making in gestation. And before that there was a whole lot of planning.
"There are not many of these animals in captivity so she was a valuable animal.
"But she was also a sweet little animal and we wanted to do the best for her."
Willow with Melbourne Zoo veterinary nurse Jenny Kingston.
He recalled Willow's playful nature, and the way the calf would try to grab its bottle back whenever it was taken away.
Mr Moss said the elephant was "a little fighter".
"She had a strong will to live, but circumstances beyond her control meant she couldn't make it," he said.
"She was a feisty one to the very end. The mind was there but the body wasn't able"
Zoo director Kevin Tanner thanked the "absolutely devastated" staff for their efforts and said they would also have access to grief counsellors.
He also thanked the community for its outpouring of support for Willow.
The calf's body has been taken to the Werribee vet school, where Mr Tanner said it would be disposed of.
Animal rights campaigners say that Willow's tragic early death supported their contention that zoos should neither keep nor try to breed elephants.
PETA Australia's campaign coordinator Claire Fryer said that attempting to breed the pachyderms in captivity often ends in tragedy and called on Melbourne Zoo to close their elephant exhibit.
"Given the lack of stimulation and exercise and the inbreeding inherent at zoos, the infant-mortality rate for elephants is almost triple the rate in the wild," Ms Fryer said in a statement.
Despite this, she added, "Melbourne Zoo continues to breed these intelligent animals in an effort to churn out more cash cows
"Zoos around the world have closed their elephant exhibits or announced plans to phase them out, citing their own inability to meet the significant needs of these animals.
"It's time for Melbourne Zoo to do the same."
Mr Tanner said the Zoo would continue with its breeding program.
