Association Between Measures Of Milk Quality And Risk Of Violative Antimicrobial Residues In Grade-A Raw Milk

Objective-To determine whether bulk-tank standard plate counts or plate loop counts and bulk-tank somatic cell counts (SCC) were associated with detection of violative antimicrobial residues in milk from dairy cattle.Design-Longitudinal study.Procedure-Information for 1994 through 1997 was obtained from a large milk marketing cooperative that operated in multiple states throughout the northeastern and midwestern United States (16,831 herd-years of information from 6,546 farms) and from the Ohio Department of Agriculture Grade-A Milk Certification Program (12,042 herd-years of information from 4,022 farms). Data were analyzed by use of multivariate logistic regression.Results-For both data sets, odds that a violative antibiotic residue would be detected increased as mean SCC for the herd-year increased. Standard plate counts and plate loop counts were not associated with odds that a violative antibiotic residue would be detected.Conclusions and Clinical Relevance-Results of this study suggested that the odds that a violative antibiotic residue would be found in bulk-tank milk increased as mean SCC for the herd-year increased. This suggests that management practices that would be expected to influence SCC may also influence the risk of antibiotic residue violations.