Preventing Antibiotic Residues in Milk

Guidelines to help keep milk free of antibiotic residues.

Prevent disease to minimize the use of antibiotics:
  • Maintain good herd health; use best management practices for animal husbandry.
  • Diagnose sick animals early and accurately; take immediate action.
  • Practice farm and herd biosecurity.
  • Mark and separate treated cows from the milking herd.


Follow directions on drug and medicated feed labels:
  • Note whether drug is approved for lactating cows.
  • Follow instructions for treatment dosage, frequency and route of administration.
  • Follow label directions for medicated feed, and never use feed intended for other livestock.
  • Adhere to recommended milk-withholding time.
  • If you treat cows “extra-label,” test all extra-label-treated cows before putting them back into the milking line.
  • Withholding times for extra-label treatments are unknown.
  • Test all dry-treated cows, especially those that freshen early, before putting them back into the milking line. Dry-cow treatments last longer.


Keep good treatment records:
  • Make one person responsible for treating cows and monitoring records.
  • Record the following:
    • ID numbers of treated cows
    • Dates and times of treatment
    • The antibiotic used, its dosage, frequency and route of administration
    • The drug withdrawal period
  • Review and check records at every milking.
  • Be informed of treatments given by your veterinarian.


Keep milk from treated cows out of the milking line:
  • Withhold milk from any cow receiving oral, intramuscular, udder infusion or intrauterine antibiotic treatments and some salves and sprays.
  • Segregate and test all purchased herd replacements before introducing them into the milking herd.
  • Milk all treated animals last.
  • Discard milk from all four quarters of udder, even if only one quarter was treated.
For information or to order:

Call IDEXX Technical Services, 1-800-321-0207.