New plan tried to keep impala safe, zoo says
4/12/2007Toledo Zoo officials were trying to prevent a repeat of an accident that killed an impala a year ago when they chose a completely new method of preparing the flighty animals for shipping.
But the new travel plan proved no protection for 21-month-old Hurley, who died last week while being prepared for shipment to the Milwaukee County Zoo, zoo officials told the zoo board's animal care committee yesterday.
A year earlier, Hurley was with another impala that died as they were being prepared for transport to a zoo in Battle Creek, Mich.
Hurley and Jack were tranquilized and put into a crate together for their trip to Michigan. As soon as the crate doors were closed, the 110-pound animals panicked.
"They just ricochetted,'' Zoo Director Anne Baker said.
When zoo staff opened the crate again, Jack had a fractured vertebrate and had to be euthanized. Hurley had bruises and cuts on his face, but no other injuries evident.
After last year's accident, zoo officials hoped to find a transport method that was safer for the high-strung animals. Instead of crating the impala together, they would be housed separately. Instead of simply tranquilizing them, they would be anesthesized completely and moved into the crates.
"The previous impala death, that plan of crating - this is exactly the opposite, this way we went to,'' said Dr. Chris Hanley, the zoo's associate veterinarian. "We tried to do something different."
But Hurley failed to recover normally from the anesthetic, delaying shipment.
While he seemed to be recovering around midnight, the animal was found dead the next morning. The second impala was shipped successfully to Milwaukee.
A necropsy revealed that vertebrate in Hurley's neck had been damaged some time ago. Hurley was missing a disk between two vertebrate. Those gristly pads serve as cushions between the bones. Where the disk was missing, the bone surfaces rubbed together. Signs of wear were apparent during the post-mortem exam.
Dr. Hanley speculates that the movement involved with anesthesia and recovery somehow aggravated the injury, pinching a nerve that controls the diaphragm, which made the animal stop breathing.
Laboratory results from the necropsy will not be available for more than a month, and it's not certain if those results will prove important in determining an exact cause of death.
Ms. Baker said shipment of impalas is problematic for all zoos because of the animal's strong desire to flee anything unusual.
She said Hurley may have been hiding an earlier injury. A medical exam prior to the attempted shipment revealed no problem. "All wild animals, and particularly these hoof stock, they have evolved not to show any signs of illness, sickness, disability because that's sort of like saying, 'I'm here! Eat me!' "
Contact Jenni Laidman at:
jenni@theblade.com
or 419-724-6507.