The giraffe that was found dead at the Greater Vancouver Zoo in November died of a degenerative brain disease, officials said.

The zoo said lab tests revealed 12-year-old Jafari was suffering from encephalomalacia, a type of disease common among animals with a fermenting stomach. According to Chelsea Himsworth, a veterinary pathologist with the B.C. government who conducted the tests, a fermenting stomach is filled with bacteria and is very sensitive. Any small changes in digestion can cause the bacteria to produce toxic substance that can affect the brain, Himsworth said.

“Given all the information that we have, Jafari died very quickly and fortunately,” said veterinarian Bruce Burton, who cared for Jafari for most of the animal’s life, in a written statement. “There would have been little or no suffering.”

Jody Henderson, the zoo’s general manager, said the cause of death came as a surprise, as there were no noticeable symptoms that Jafari was suffering from a brain disease.

“Definitely there were no signs of anything wrong with him,” she said. “Food, eating, drinking, bathroom--everything was completely normal behaviour.”

Henderson said there is little data available about encephalomalacia in giraffes because it is very difficult to remove a giraffe’s brain to study it.

Jafari was found collapsed and lifeless in his heated barn on Nov. 4. At the time, Burton said Jafari was healthy, with a good layer of insulating fat to keep him warm, and there were no signs of physical trauma.

Jafari was the third giraffe to perish at the zoo within a year. His three-year-old offspring Amryn died in 2011, and Amryn’s mother, 23-year-old Eleah, died six days later. Amryn and Eleah’s causes of death are still undetermined.

One surviving giraffe remains at the zoo.