Rare rhino born in Melbourne dies

A rare southern white rhino baby born at Melbourne's Werribee Zoo has died.

Nicknamed Salt, the three-day-old rhino was put down on Tuesday after developing an aggressive and incurable stomach infection.

Senior veterinarian Dr Natalie Rourke said the infection had been passed on from the rhino's mother Si Si.

"Her older sister Kipenzi was born with a similar infection and so we were able to identify it quickly and begin antibiotic treatment," she said.

While the rhino, who the zoo intended to give a traditional African name, was initially feeding well she began to lose interest in milk and showed signs of discomfort on Sunday.

Dr Rourke said the infection was causing irreparable damage to the rhino's stomach and surgery would only have prolonged the pain.

Zoo director Sally Lewis said it was a difficult time for the zoo, particularly the vet and animal care teams.

"The loss of this calf is a huge blow for us, particularly with a species that is so under threat," she said.

Mum Si Si is healthy and has rejoined her herd.