Evaluation of certification in the Milk and Dairy Beef Quality Assurance Program and associated factors on the risk of having violative antibiotic residues in milk from dairy farms in Michigan

Objective-To determine whether certification in a Milk and Dairy Beef Quali ty Assurance Program (MDBQAP) was associated with a reduced risk of having antibiotic residues in milk and to define specific management factors that may have predisposed dairy farms to having violative antibiotic residues in milk. Sample Population-124 dairy farms in Michigan that had greater than or equa l to 1 violative residue in milk during 1993 and 248 randomly selected cont rol farms in Michigan that did not have violative residues in milk during 1 993. Procedure-A pretested structured questionnaire was mailed to case and contr ol farms. A conditional multivariate logistic regression model was develope d to determine risk factors associated with having a violative antibiotic r esidue in milk. Results-Certification in the MDBQAP did not significantly reduce the risk o f having a violative antibiotic residue. Annual treatment of > 10% of a her d for metritis was associated with a reduced risk of having a violative res idue. Evidence suggested that a routine request for a milk processor to per form residue testing was associated with a decreased risk of having had a v iolative antibiotic residue, but routine on-farm residue testing was associ ated with an increased risk of having had a residue. Conclusions and Clinical Relevance-MDBQAP certification was associated, alt hough not significantly, with a reduced risk of having violative antibiotic residues in milk. Risk factors significantly associated with violative ant ibiotic residues are addressed by various critical control points in the MD BQAP and may be indicators for strengths and weaknesses of MDBQAP.