POWELL, Ohio (AP) - The Columbus Zoo and Aquarium says a 6-year-old giraffe has died, four days after a cesarean section was unable to save her calf.

A zoo release says the Masai giraffe, Cami, collapsed Saturday morning and was unable to rise. She died soon afterward. Initial bloodwork suggests acute kidney failure, but a full necropsy will be conducted.

She had shown signs of labor Tuesday afternoon. The calf was being birthed rear hooves first, and the zoo says such calves rarely survive.

A large-animal surgeon performed a cesarean section Tuesday night, but couldn't save the calf, which had serious congenital defects. The zoo says such deliveries are rare for giraffes and are only tried as a last resort.

Cami came to the zoo in central Ohio from Nashville, Tennessee, in 2013.