Veterinary drugs

The project aims to facilitate the identification of safe alternatives to diclofenac and introduce these into the veterinary marketplace. This work has involved a survey of the clinical use of NSAIDs in vultures and other scavenging birds and is involving safety testing of alternative NSAIDs on vultures in Southern Africa and India.

Many millions of doses of diclofenac have been used by vets and farmers across South Asia as painkiller for cattle and other animals. Therefore finding a safe alternative was a key step to removing it from the system. Fortunately one such alternative, meloxicam, has been identified. Ketoprofen has been tested on vultures and found to be toxic, but so far there has been no government action to ban its veterinary use. Other alternative drugs are also in use and being introduced to the veterinary painkiller market, but their safety to vultures is completely unknown.

Research into a safe alternative drug has being undertaken by the RSPB, in collaboration with the Indian Veterinary Research Institute (IVRI), the Bombay Natural History Society and the Faculty of Veterinary Science at the University of Pretoria (South Africa) and the Rhino & Lion Wildlife Conservation’s Vulture Programme. In order to help identify safe alternatives we first undertook a
questionnaire survey of veterinarians at zoos, raptor rehabilitation centres and raptors collections, asking them for evidence of the safety of toxicity of NSAIDs. These results identified meloxicam as a potential safe drug, as well as raising safety concerns about the NSAIDs carprofen, flunixin and ketoprofen (see ‘Cuthbert et al 2006′ and ‘Toxicity of NSAIDs to Gyps vultures: a new threat from ketoprofen’). Testing of the safety of meloxicam was undertaken on captive non-releasable African white-backed vultures, an abundant and non-threatened species widely distributed across Africa. Visits were also made by researchers from BNHS and IVRI to ensure that testing methods were appropriate for later use in India. After testing meloxicam, at increasing doses with these captive birds, a larger number of wild African white-backed vultures were captured in Namibia, through the assistance Maria and Jörg Diekmann, and the Rare and Endangered Species Trust (REST). Over a long weekend, Maria and Jörg with the assistance of a large group of experienced and keen volunteers successfully captured 66 African white-backed vultures. A total of 20 of these birds were treated with meloxicam at the estimated maximum level of exposure that vulture could potentially encounter this drug (estimated from a bird consuming 1 kg of liver tissue from a cow dying shortly after receiving a standard veterinary dose of meloxicam). All of the birds survived and their blood parameters and behaviour were normal. A paper detailing the results of this safety testing work was published in early 2006 (Swan et al 2006), helping provide crucial momentum to the advocacy programme’s efforts to ban diclofenac, by providing vets with a vulture safe alternative to diclofenac.

Following these trials in Southern Africa, work on the safety of meloxicam was repeated on two of Asia’s critically endangered vulture species (white-backed and long-billed vultures) held at one of the captive breeding centres, as well as testing the safety of meloxicam to other scavenging birds. The trials again found no indication of harm, with all birds surviving and no evidence of elevation of the concentration of uric acid in the blood, which occurs shortly before death in vultures treated with diclofenac. This trial and the work in South Africa tested meloxicam by administering it directly to vultures (by giving it orally through a tube) and by feeding tissues of livestock that were slaughtered shortly after they had been treated with a veterinary dose of the drug (thereby replicating the way that wild birds are exposed to meloxicam). The work in India was  published providing further impetus to the promotion of this safe drug in Asia (Swarup et al 2007).