Development and Model Testing of Antemortem Screening Methodology To Predict Required Drug Withholds in Heifers

Abstract

A simple, cow-side test for the presence of drug residues in live animal fluids would provide useful information for tissue drug residue avoidance programs. This work describes adaptation and evaluation of rapid screening tests to detect drug residues in serum and urine. Medicated heifers had urine, serum, and tissue biopsy samples taken while on drug treatment. Samples were tested by rapid methods and high-performance liquid chromatography (HPLC). The adapted microbial inhibition method, kidney inhibition swab test, was useful in detecting sulfadimethoxine in serum, and its response correlated with the prescribed withdrawal time for the drug, 5 to 6 days posttreatment. The lateral flow screening method for flunixin and beta-lactams, adapted for urine, was useful in predicting flunixin in liver detected by HPLC, 96 h posttreatment. The same adapted methods were not useful to detect ceftiofur in serum or urine due to a lack of sensitivity at the levels of interest. These antemortem screening test studies demonstrated that the method selected, and the sampling matrix chosen (urine or serum), will depend on the drug used and should be based on animal treatment history if available. The live animal tests demonstrated the potential for verification that an individual animal is free of drug residues before sale for human consumption.

Comparative plasma and interstitial fluid pharmacokinetics and tissue residues of ceftiofur crystalline‐free acid in cattle with induced coliform mastitis

“…Following incubation, the agar color was compared to the reference card provided by the manufacturer to determine the test result. The sensitivity of this assay is not reported by the manufacturer but others have reported the lower limit of detection to be 4 ppm (Jones et al., ).…”

“…The fact that none of the Kidney Inhibition Swab (KIS ™ ) tests were positive on the DIS animals is not surprising given the fact that all the kidney tissues were below the tolerance. In addition, the reported sensitivity of this assay is 4 ppm, which is 10‐fold higher than the tolerance for CEF (Jones et al., ), making it a questionable choice for screening cull dairy cattle for CEF residues. This is thought‐provoking as cull dairy cows have the highest incidence of violative residues among adult cattle classes (USDA, ) and CEF is the most commonly used antimicrobial in the US dairy industry (Sawant et al., ; Schuler et al., ; Zwald et al., ).…”

Optimization and Validation of a New Microbial Inhibition Test for the Detection of Antimicrobial Residues in Living Animals Intended for Human Consumption

“…The analysis of antimicrobial residues in animals prior to slaughter has thus been attracting increased attention in recent years [18,19]. Several issues need to be solved, however, before implementing a methodology for in vivo testing for antibiotics.…”

Impact of disease in dairy cows on ceftiofur pharmacokinetics, withdrawal times and emergence of antimicrobial resistance

“…The fact that none of the kidney inhibition swab (KIS™) tests were positive on the DIS animals is not surprising given the fact that all the kidney tissues were below the tolerance. Additionally, the reported sensitivity of this assay is 4 ppm, which is 10-fold higher than the tolerance for CEF (Jones et al, 2014), making it a questionable choice for screening cull dairy cattle for CEF residues. This is thought-provoking since cull dairy cows have the highest incidence of violative residues amongst adult cattle classes (USDA, 2017b) and CEF is the most commonly used antimicrobial in the US dairy industry (Zwald et al, 2004;Swant et al, 2005;Schuler et al, 2017).…”

“…Subsequently, it has been suggested that these new testing methodologies are more sensitive to CEF residues. However, published data suggests that the KIS TM test has a sensitivity for CEF in kidney tissue of 4 ppm, nearly 10x higher than the tolerance (Jones et al, 2014). Therefore, the KIS TM test is not very sensitive to CEF compared to the bovine tolerance.…”