ISU College of Veterinary Medicine Announces New Screening Test for Milk Residues

Dr. Hans Coetzee, College of Veterinary Medicine, (515) 294-7424
Ms. Tracy Raef, College of Veterinary Medicine, (515) 294-4602 

June 6, 2012

Access to a highly sensitive and specific confirmatory test that allows dairy producers to check milk samples for drug residue concentrations is now available through the Cyclone Custom Analyte Detection Service (CYCADS) at Iowa State University’s College of Veterinary Medicine.

Dairy farmers use pharmaceutical compounds every day for the treatment of painful and economically significant conditions such as mastitis and lameness. To protect the public from any drug residues that may pose a risk to human health, milk samples are tested by regulatory authorities, using assays that are more sensitive than conventional screening tests currently used on the farm.

This new test will provide U.S. dairy veterinarians with an assay similar to the one used by the Food and Drug Administration and other regulatory authorities, for a fraction of the cost normally associated with this type of test when done by other laboratories.

The test assay allows dairy producers and veterinarians to:

  • identify and quantify drug concentrations in samples that tested positive on conventional screening tests
  • determine drug depletion in milk after a drug has been administered in an extralabel manner
  • check whether an accepted drug treatment protocol is being adhered to in a herd
  • analyze milk from recently purchased cattle prior to them joining the herd as part of a biosecurity protocol
  • determine whether dairy feed has been adulterated with antimicrobials used in beef and swine production.

The cost of the tests range from $50 to $75 per sample, and the turnaround time is two business days.

“The CYCADS milk residue screening assay will allow veterinarians to easily compare the drug screening results from individual cow or bulk tank milk samples with the established tolerance or “safe concentration” for pharmaceutical compounds assuming these have been established,” said Dr. Hans Coetzee, associate professor at Iowa State’s College of Veterinary Medicine. “Where no tolerance has been established we will report the results accordingly. This will allow veterinarians to assist their clients in making a science-based determination as to whether the milk is suitable for consignment.”

For more information about the testing service and how to submit samples, visit:

CYCADS is a group of veterinary pharmacologists and toxicologists supported by analytical chemists who focus on high-throughput, pharmacology-focused analytical services. The Iowa State’s Veterinary Diagnostic Laboratory is the only veterinary laboratory offering such service. The goal of CYCADS is to develop innovative tests aimed at improving the health and welfare of livestock and safeguarding international trade agreements and public health.