Purpose of with holding periods

In the past the ACVM Group imposed withholding periods (WHPs) for a number of reasons, for example:

• to avoid damage to or downgrading of primary produce;
• to ensure substances were fully cleared from the system of racing animals (i.e. horses and grey-hounds);
• to compensate for a lack of information on residues.

Consequently, it was difficult for parties to know the exact purpose of the WHP and how it was determined.

In future WHPs will be imposed only to ensure that maximum residue limits (MRLs) in foods for humans are not exceeded. For example, new oral zinc, oral copper or oral zinc/copper combination products will have a nil WHP because there is no MRL set for food for these minerals.

If licensees wish to claim a nil WHP for products already licensed, they should apply to the ACVM Group for a label change.