December 10, 2009

Drug For Cattle Proves Deadly For Vultures

A second veterinary pain drug used to treat cattle could be deadly to endangered vultures that feed on the carcasses of livestock, according to a study released Wednesday.

The death toll of the slender-billed and oriental white-backed vultures has reached the millions in South Asia, mostly in India, after consuming the carcasses of sick cattle that had been treated with anti-inflammatory painkiller diclofenac, reported the Associated Press.

Researchers writing in the Royal Society journal Biology Letters have now discovered that a second drug, ketoprofen, has also proven to be toxic to vultures and should be discontinued for the treatment of livestock in Asia.

"Surveys of livestock carcasses in India indicate that toxic levels of residual ketoprofen are already present in vulture food supplies," the researchers wrote.

"Consequently, we strongly recommend that ketoprofen is not used for veterinary treatment of livestock in Asia and in regions of the world where vultures access livestock carcasses."

The drug causes the birds to suffer acute kidney failure within days of exposure, which is the same toxic effect caused when vultures feed on the carcasses of animals treated with diclofenac, reported BBC.

Researchers formerly had thought that ketoprofen would not be as harmful since it is metabolized faster by cows, and converted within hours into a form that is not dangerous to vultures, but an international team of scientists that carried out safety tests on the drug, found that doses given to cattle in India were enough to kill the birds.

Tens of millions of vultures played a vital part in South Asian ecosystems before the introduction of diclofenac in the early 1990s. According to Britain's Royal Society for the Protection of Birds, populations of the three species of the critically endangered, griffon-type vultures are now believed to have fallen by as much as 97 percent.

Vultures are key to the disposal of carcasses, cutting down on stray dog and rat populations that also feed on dead cattle and are known to spread disease among humans.

"From millions of individuals in the 1980s, vultures have simply disappeared from large swaths of India, Pakistan and Nepal, and at least three species have been brought to the brink of extinction," said Richard Cuthbert, one of the study's authors and a scientist with the Royal Society.

"The rate of decline of these magnificent birds is staggering," he said.

"For the oriental white-backed vultures, for every two birds alive last year, one will now be dead, and this is all because of the birds' inability to cope with these drugs in livestock carcasses, the birds' principal food source."

Over two years ago, Indian officials were forced to ban the use of diclofenac because of how quickly the vulture populations were dwindling. Now conservationists are seeking a similar move from authorities with the second drug ketoprofen and make sure that farmers only use meloxicam, which has been proven safe.

"We would like to see other safe alternatives, but it should be the responsibility of the Indian pharmaceutical industry to test these to determine their safety to vultures," said Vibhu Prakash, director of the vulture program of the Bombay Natural History Society in India.


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