Ministry of Agriculture, Food and Rural Affairs

Preventing Antibiotics In Your Milk

Since residues in milk can be traced back to improper use of antibiotics at the farm, producers must ensure that necessary precautions are taken when treating livestock with antibiotics.

Procedures to follow

• Administer drugs only on the advice of your herd health veterinarian.
• Follow veterinarian's instructions exactly for the method of administration (such as intramuscularly, orally, etc), the dosage amount and timing.
• Identify treated animals with markings or bands. Ensure everyone involved in milking is aware of which animals have been treated and follow special milking procedures.
• Ensure milk from treated animals does not get into the bulk tank.
• Follow the withholding time specified by your veterinarian.
• Make a written and permanent record of the animal(s) being treated, dosages, date(s) administered and withdrawal times (milk and meat).
• If you are uncertain of antibiotic residues, test the milk using an appropriate inhibitor test kit prior to re-entry of treated does into the milking line-up.

Steps to take if you have mistakenly milked a treated animal

If you have milked a treated animal and suspect the milk has entered the bulk tank:

• Stop milking.
• Dump the milk already in the bulk tank.
• Thoroughly rinse and clean all milking equipment including hoses, pipelines and bulk tank before resuming milking.

Test if you Suspect

If you are uncertain about antibiotics in your milk, have it tested before shipping. Test kits specifically for goat milk are available for the beta-lactam, tetracycline and sulfonamide families of drugs. Each test has its own benefits and limitations in cost, speed, sensitivity and efficacy. (Note that some test kits are approved for bovine milk only and may produce inaccurate test results when used to test goat milk.)

Testing services are available from veterinarian clinics, some processors and the Agriculture and Food Laboratory, University of Guelph at 1-519-767-6299 (Toll Free at 1-877-863-4235). Information on their services can also be found on the Agriculture and Food Laboratory website.

The major suppliers of test kits for the North American dairy goat market are CHARM Sciences and Idexx Laboratories.

Figure 1: Snap test kit

A positive inhibitor test result may also be caused by:

• medicated feeds
• incomplete cleaning of all milking equipment after inadvertently milking a treated goat
• not adding a safety margin to the milk withholding time (the metabolism of the treated animal may be slower than expected which slows the rate of the drug leaving the animal's system)
• using a combination of drugs to treat an animal, which may lengthen the withholding time beyond that of each individual drug
• administering drugs in a method different from that stipulated (such as intramammary rather than intramuscular), or giving a higher dosage than recommended
• withholding milk only from treated halves

For more information on what you can do to prevent antibiotics from ending up in your bulk tank of milk, refer to the fact sheet Troubleshooting Antibiotic Residues in Goat Milk or contact your Raw Milk Specialist.