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Keywords:

  • BSE crisis;
  • carcass;
  • disease;
  • quinolones;
  • livestock;
  • veterinary drugs;
  • vultures

Abstract

Veterinary drugs present in livestock carcasses may be ingested by scavengers and may cause important declines in their populations, as reported for diclofenac in Asia. Drug content of carcasses may depend on the prevailing livestock operations and legal regulations for carcass elimination. In Spain, the main stronghold of vultures in Europe, legal measures to mitigate the spread of bovine spongiform encephalopathy (BSE) have caused the lack or scarcity of unstabled livestock carcasses available for avian scavengers, and the parallel increase in use of dumps of livestock carcasses supplied by farms, especially of intensively medicated pigs and poultry. We evaluated temporal trends in the presence and concentration of antibiotics and other veterinary drugs, and their associated health impacts on three vulture species, due to the ban of abandoning unstabled livestock carcasses in the countryside since the BSE crisis. An increasing presence and concentration of antibiotics since the BSE crisis, and residues of three non-steroidal anti-inflammatories (NSAIDs) and four anti-parasitics were found in the vultures. Quinolones were associated with infection by opportunistic pathogens in the three species and with generalized damage to internal organs in the cinereous vulture, but no clear health impacts of NSAIDs and anti-parasitics were found. Given that there is no evidence of BSE transmission risk due to the abandonment of unstabled livestock carcasses in the countryside, this traditional practice in the Mediterranean region should be legalized in order to increase the availability, dispersion and quality of food for threatened scavengers. Once legalized, this practice should be prioritized over the spatially concentrated disposal of large amounts of carcasses from medicated stabled livestock to reduce the risk and effects of drug ingestion and acquisition and transmission of pathogens by vultures.