Multi-Residue Analysis of Veterinary Drug Residues in Beef and Poultry Products from Abattoirs in Oyo State, South West Nigeria

Unsupervised veterinary drug administration, inadequate pre-slaughter withdrawal periods, and poor documentation of treatment records in Nigerian livestock production systems create significant risks of veterinary drug residues in meat products that exceed maximum residue limits and pose direct consumer health risks. This study conducts multi-residue analysis of veterinary drug residues in beef and poultry samples collected from five registered abattoirs in Oyo State, South West Nigeria. Target analytes include tetracyclines, sulfonamides, macrolide antibiotics, and beta-agonists (particularly clenbuterol) representing the drug classes most commonly reported in Nigerian livestock systems. Sample preparation employs modified QuEChERS extraction followed by solid-phase extraction cleanup. Analysis is performed by high-performance liquid chromatography tandem mass spectrometry (LC-MS/MS) using multiple reaction monitoring mode for simultaneous quantification of twenty-two target compounds. Method validation is conducted according to European Union Decision 2002/657/EC criteria for veterinary drug residue analytical methods. Results are compared against European Union maximum residue limits and Codex Alimentarius maximum residue limits. A structured survey of livestock farmers and veterinary drug vendors examines prescribing practices, drug procurement channels, and awareness of withdrawal periods. Statistical analysis identifies the most prevalent residue violations by drug class and meat type. Findings inform the Department of Veterinary and Pest Control Services and the National Agency for Food and Drug Administration and Control about critical residue violation hotspots in South West Nigerian abattoirs. Keywords: veterinary drug residues, multi-residue analysis, LC-MS/MS, beef, poultry, Oyo State