title: Short communication: use of the BetaStar Plus assay for detection of ceftiofur antimicrobial residues in milk from individual cows following intramammary treatment for mastitis.
abstract: Development and use of on-farm assays to detect antimicrobial residues in milk is important to reduce the risk of violative residues in marketed milk. The objective of this study was to evaluate the effectiveness of a lateral-flow immunodiagnostic assay (BetaStar Plus, Neogen Corp., Lansing, MI) in detecting ceftiofur residues in milk from individual cows treated for mastitis. This assay is currently approved by the US Federal Drug Administration (FDA) for detecting β-lactam residues in commingled milk. Forty-five dairy cows with clinical mastitis from 4 dairy farms were enrolled and treated intramammary with 125 mg of ceftiofur hydrochloride (Spectramast LC, Zoetis, Madison, NJ) according to the manufacturer's label recommendation. Composite milk samples were collected (A) before first intramammary antimicrobial treatment, (B) before the last intramammary antimicrobial treatment, (C) the last milking of the product-labeled milk withhold, (D) the first milking after the product-labeled milk withhold had been met, and (E) 72 h after the product-labeled milk withhold had been met. Samples were tested using the BetaStar Plus assay within 48 h of collection. Parallel samples were analyzed by liquid chromatography-tandem mass spectrometry (LC-MS/MS) and for somatic cell count and milk components. The BetaStar Plus assay identified 6.7, 60.0, 46.7, 22.2, and 6.7% positive samples at each of the respective time points. The assay had sensitivity and specificity of 100 and 84.7%, respectively, compared with liquid chromatography-tandem mass spectrometry analysis using FDA published residue tolerance levels for ceftiofur (or ceftiofur metabolites) as a threshold. The BetaStar Plus assay could be useful for detecting ceftiofur residues in milk from individual cows following intramammary treatment for mastitis before the milk is shipped for processing.
authors.affiliation: Department of Large Animal Clinical Sciences, Michigan State University, East Lansing 48895. Electronic address: grooms@cvm.msu.edu.
authors.forename: D L
authors.initials: DL
authors.lastname: Grooms
authors.affiliation: Department of Large Animal Clinical Sciences, Michigan State University, East Lansing 48895.
authors.forename: B
authors.initials: B
authors.lastname: Norby
authors.affiliation: Department of Large Animal Clinical Sciences, Michigan State University, East Lansing 48895.
authors.forename: K E
authors.initials: KE
authors.lastname: Grooms
authors.affiliation: Department of Large Animal Clinical Sciences, Michigan State University, East Lansing 48895.
authors.forename: E N
authors.initials: EN
authors.lastname: Jagodzinski
authors.affiliation: Department of Large Animal Clinical Sciences, Michigan State University, East Lansing 48895.
authors.forename: R J
authors.initials: RJ
authors.lastname: Erskine
authors.affiliation: Department of Large Animal Clinical Sciences, Michigan State University, East Lansing 48895.
authors.forename: L W
authors.initials: LW
authors.lastname: Halbert
authors.affiliation: Department of Veterinary Diagnostic and Production Animal Medicine, Iowa State University, Ames 50011.
authors.forename: J F
authors.initials: JF
authors.lastname: Coetzee
authors.affiliation: Department of Veterinary Diagnostic and Production Animal Medicine, Iowa State University, Ames 50011.
authors.forename: L
authors.initials: L
authors.lastname: Wulf
authors.affiliation: Neogen Corporation, Lansing, MI 48912.
authors.forename: J A
authors.initials: JA
authors.lastname: Rice
mesh_terms: D000818:Animals; D000900:Anti-Bacterial Agents / Q000032:analysis* / Q000627:therapeutic use; D001681:Biological Assay / Q000379:methods*; D002417:Cattle; D002452:Cell Count; D002511:Cephalosporins / Q000032:analysis* / Q000627:therapeutic use; D002853:Chromatography, Liquid; D004350:Drug Residues / Q000032:analysis*; D005260:Female; D008414:Mastitis, Bovine / Q000188:drug therapy*; D008892:Milk / Q000737:chemistry*; D053719:Tandem Mass Spectrometry
chemical_list: D000900:Anti-Bacterial Agents; D002511:Cephalosporins; C053503:ceftiofur
keywords: antibiotic; milk; residue