The animal was injected with the wrong syringe during surgery.
COLUMBUS (AP) -- A giraffe died in April at the Columbus Zoo and Aquarium after the chief veterinarian injected the wrong drug during an operation, according to a federal investigation.
Zoo officials did not mention the error by Dr. Michael Barrie when announcing the death. Instead, officials attributed the death to heart failure while under anesthesia.
But a report by the U.S. Department of Agriculture said Dr. Barrie grabbed the wrong syringe during the operation to remove an epoxy shield from one of the giraffe's hoofs.
Assistant Zoo Director Donald Winstel said zoo officials knew of the error the day that the giraffe, named Kenya, died, but they were not certain it was the cause of death until a post-mortem examination confirmed it a month later.
The federal report said Dr. Barrie had intended to administer atropine, a drug to stabilize the giraffe's heart rate, but he instead injected atipamazole, a drug used to awaken an animal from anesthesia, the report said.
Dr. Barrie, the zoo's chief veterinarian for four years, said the two syringes were lying side by side.
"I picked up the wrong one. It caused a cascading effect, and she died," Dr. Barrie said.
Dr. Barrie said he has never made a similar mistake in his 24-year career. To guard against a similar error in the future, syringes will be color-coded, he said.
Zoo officials said they remain supportive of Dr. Barrie and continue to have confidence in him.
Lisa Wathne with the People for the Ethical Treatment of Animals in Seattle, called the death "absolutely appalling."
"If this were a human, that doctor would be facing an incredibly large malpractice suit," said Wathne, adding that PETA will file a formal complaint with the Agriculture Department seeking sanctions against the zoo.
Three other animals died in April at the Columbus zoo.
Another giraffe, named Tsavo, was euthanized after zoo keepers found him lying in a cage and couldn't get him to stand. A necropsy showed Tsavo had torn muscle fibers throughout his body.
A day earlier, two zebras died minutes after being moved to a temporary enclosure outside Columbus. They got spooked and slammed into fence posts, breaking their necks, officials said.
The federal report found no errors in the treatment of Tsavo or the zebras.