Screening and Confirmatory Analyses of Flunixin in Tissues and Bodily Fluids after Intravenous or Intramuscular Administration to Cull Dairy Cows with or without Lipopolysaccharide Challenge.
Weilin L Shelver, David J Smith, Lisa A Tell, Ronald E Baynes, J W Schroeder, Jim E Riviere
Index: J. Agric. Food Chem. 64 , 336-45, (2016)
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Abstract
Twenty cull dairy cows (645 ± 83 kg) were treated with 2.2 mg/kg bw flunixin by intravenous (IV) or intramuscular (IM) administration with, or without, exposure to lipopolysaccharide in a two factor balanced design. The usefulness of screening assays to identify violative flunixin levels in a variety of easily accessible ante-mortem fluids in cattle was explored. Two animals with violative flunixin liver residue and/or violative 5-hydroxy flunixin milk residues were correctly identified by a flunixin liver ELISA screen. Oral fluid did not produce anticipated flunixin concentration profiles using ELISA determination. One cow that had liver and milk violative residues, and one cow that had a milk violation at the prescribed withdrawal period were correctly identified by flunixin milk lateral flow analyses. The ratio of urinary flunixin and 5-hydroxy flunixin may be useful for predicting disruption of metabolism caused by disease or other factors potentially leading to violative liver flunixin residues.