Depletion of Intramuscularly Injected Ceftiofur from the Milk of Dairy Cattle

Abstract

Ceftiofur sodium, a new broad-spectrum cephalosporin, has been approved in the US, Canada, and several other countries throughout the world to treat bovine respiratory disease in cattle and dairy cows. In Experiment 1, 6 lactating cows were intramuscularly treated with 2.29 mg of [14C]ceftiofur/kg of BW daily for 5 d. In Experiment 2, 30 additional cows at three locations were similarly treated with 2.2 mg of ceftiofur (unlabeled)/kg of BW. Milk was collected every 12 and 24 h after each dose and every 12 h up to 5 d after the last dose. The majority of milk samples, both during treatment (12 and 24 h after each dose) and after the last dose (up to 5 d following ceftiofur treatment), were negative by screening procedures based on microbial inhibition (Delvotest-P, Bacillus stearothermophilus disk assay, and cylinder plate assays). The receptor-binding Charm Test II assay, which has a limit of detection of .005 ppm of ceftiofur, gave positive tests for milk samples up to 48 h following treatment. When the Charm Test II assay is used with .008 IU/ml of penicillin as a positive control, 44% of the samples from individual cows were negative at 12 h posttreatment. Ninety percent of the samples from individual cows were negative at 24 h after the last treatment. The use of ceftiofur in dairy cattle in accordance with the label directions does not result in total residues in milk higher than the FDA-calculated safe concentration of 1-ppm ceftiofur equivalents. The milk from individual cows did not test positive by the commercial screening assays examined in this study, except for the Charm Test II. The Charm Test II was 90% negative using the Charm Sciences criteria at 24 h after the last treatment.

Validation of a Rapid Lateral Flow Test for the Simultaneous Determination of β-Lactam Drugs and Flunixin in Raw Milk

“…Samples containing penicillin G, amoxicillin, cephapirin, ampicillin, and ceftiofur were tested and commingled in 2007 and stored at -80°C (12). These concentra tions were verified by HPLC analysis prior to use (2,3,7,9,14,24). In the spring of 2010, CVM collected incurred residue milk samples by treating three cows with flunixin after it was verified that the cows were healthy and had not been treated for the preceding 30 days.…”

A simple method for electroanalytical determination of ceftiofur in UHT milk samples using square-wave voltammetry technique

“…This MRL, along with those established for other edible tissues, corresponds to an intake of approximately 87% of the ADI for a standard diet [3]. CF metabolism has been described in rats [4], dairy cattle [5], and swine [6]. The thioester bond in this compound is rapidly cleaved to give desfuroylceftiofur, which is further metabolized to a disulfide dimer and various desfuroylceftiofur-protein and amino acid conjugates.…”

Assessment of liquid chromatography–tandem mass spectrometry approaches for the analysis of ceftiofur metabolites in poultry muscle

“…Reported metabolites include desfuroylceftiofur (DFC), desfuroylceftiofur cysteine disulfide (DCCD), protein bound DFC and desfuroylceftiofur thiolacton (Jaglan et al 1989(Jaglan et al , 1992Gilbertson et al 1995;Berendsen et al 2009). Although no maximum residue limit (MRL) has been established for poultry muscle, it is important to realise that ceftiofur MRLs for other species are defined as the sum of all residues retaining the -lactam structure, expressed as DFC (EU/37/2010).…”