Gezi, who has been at the zoo since August 2001, collapsed and suffered cardiac and respiratory arrest at about 12:15 p.m.
Zookeepers told veterinary staff Sunday that Gezi had a decreased appetite. The giraffe received antibiotics and fluids as well as blood tests, which came back normal, according to zoo officials.
Veterinarians performed a physical exam, rechecked blood and gave Gezi additional intravenous fluids and electrolytes this morning prior to her death, zoo officials reported.
Gezi, who came to the zoo at age 2, gave birth to Terrance on May 18, 2006 and to Barbro on Feb. 25.
A necropsy was scheduled to be performed on her today and results are expected to be released early Wednesday.
An outside agency will conduct tissue processing, according to zoo officials.
The average lifespan of a female giraffe held in captivity is about 25 years.
With the loss of Gezi, the San Francisco Zoo is home to one adult male and two adult females giraffes, and two calves, one male and one female.
