Animal rights groups say elephants are stuck in tight enclosures and stand for hours on concrete floors that cause arthritis or painful and often fatal foot infections.
The jumbo row mounted earlier this year after several elephants died in zoos across the US, some from complications of sore feet.
"The state of elephant health in the US is appallingly poor," said Elliott Katz, a veterinarian and president of California-based In Defense of Animals.
Katz reviewed records of 35 zoos between 2000 and 2005 and came away disgusted and convinced the facilities were killing the elephants.
"I am sickened by members of my own profession who know the (sick) elephants need to be on soft soil to have any chance of getting better and yet they never speak out," he said.
But the zoo industry rejects such charges saying that while much could be said about elephant care in years past, zoos have gradually upgraded facilities and the almost 300 elephants in state zoos today are doing quite well.
"You have one or two people who are not working with elephants everyday, making assertions that are not based on science," said Steve Feldman, spokesman for the American Association of Zoos and Aquariums.
"Every zoo is upgrading the standards for the animals," said Willie Theisson, head elephant keeper at the Pittsburgh Zoo, who has been on the job for 29 years and cares for six elephants.(AFP)
1. arthritis n.
關節炎 (guan1 jie2 yan2)
例: My grandmother's arthritis has been getting worse lately.
2. appallingly adv.
駭人地 (hai4 ren2 di5)
例: The conditions in the village were appallingly unsanitary.
3. upgrade v.i. /v.t.
升級 (sheng1 ji2)，改善 (gai3 shan4)
例: Have you upgraded to the newest version of your operating system?
4. assertion n.
主張 (zhu3 zhang1)，斷言 (duan4 yan2)
例: Don't make assertions without facts to back them up.