Withholding periods for veterinary medicines

A withholding period for a veterinary medicine is the minimum time between giving an animal a veterinary medicine and when it may be used for food. The time depends on the animal and the medicine.

About withholding periods for vet medicines

If a veterinary medicine has been used in or on an animal, you must wait a minimum amount of time before it is used for food. This is to make sure the medicine won't pose a health risk to consumers.

Veterinary medicines registered for use in or on animals must have the withholding period printed on the label. We calculate withholding periods from residue data provided during registration of a veterinary medicine.

Determining residue withholding periods for veterinary medicines - ACVM registration standard and guideline [PDF, 148 KB]

Default withholding periods for veterinary medicines

In some cases, where no residue data is provided for a product, default withholding periods are used.

The following default withholding periods are applied to registration of veterinary medicines without residue data. These are conservative withholding periods based on all residue data provided to MPI.

These don't apply to sustained release formulations because a withholding period must be after release into the animal, not after the medicine is given to the animal.

Birds, including chickens

Meat: 63 days

Eggs: 10 days

Ruminants, including deer, cattle, sheep

Meat: 91 days

Milk: 35 days

Camelids, including llama, alpaca

Meat: 63 days

Lagomorpha, including hares, rabbits

Meat: 63 days

Monogastrics, including pigs, horses

Meat: 63 days

Fish and shellfish, including crustaceans, molluscs

Meat: 35 days

Milk withholding period based on dilution

Some veterinary medicines used on cows have 2 withholding periods stated on the label, the:

  • standard withholding period
  • dilution withholding period – this accounts for dilution of a farm's milk with milk from untreated cows.

All products with a dilution withholding period require veterinary supervision. It's up to the vet to advise on the appropriate withholding period to use in each situation. This will depend on things like:

  • the percentage of the herd being treated
  • whether the percentage treated can be calculated
  • record keeping and communication on the farm
  • stage of lactation (whether the lactating herd size is likely to change).

Using the dilution withholding period for milk: instructions for vets

To use the dilution withholding period, no more than 10% of the herd can be treated. If more than 10% is treated, use the standard withholding period.

The percentage of cows treated is calculated within a standard withholding period. For example, if a drug has a standard withholding period of 5 days, calculate the percent of cows treated over 5 days.

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