Milk withholding period for abamectin pour-on products changed from NIL to 35 days

Published 29 August 2022

The milk withholding period for ALL abamectin pour-on products has changed from NIL to 35 days.

The NZVA recommends that, while on farm, veterinarians check whether farmers have any abamectin pour-on products in use or stored on farm. It is likely these products will not have the correct withholding period on the label and farmers need to be advised about the risk of using these products effective immediately. The withholding period on these products has been extended from NIL to 35 days to ensure milk residues will be below the lower milk maximum residue level (MRL) coming into force on 19 September 2022. The new MRL will be 0.003 mg/kg.

The lowering of the milk MRL is needed to manage the risk of abamectin residues being detected in milk for New Zealand's export markets, where international limits of detection are as low as 0.002 mg/kg. It was determined that the previously approved NIL milk withholding period could result in abamectin residues above international limits. The change to all abamectin pour-on products milk withholding period was confirmed and notified to dairy industry representatives on 29 July 2022. 

The new MRL will come into force on 19 September 2022. Any abamectin pour-on products used on or after 15 August 2022 may result in residues that will exceed the new MRL. Residues may deplete to a level that will comply with the new MRL before 35 days, but this will depend on a number of factors including how quickly individual animals metabolise abamectin, the total number of animals treated in the milking herd, when they were treated, and the level of milk production of treated animals.

If there are violative residues in milk collected when the new MRL comes into force and residues in the total consignment are not diluted to below the MRL, farmers may be penalised by the dairy supply company and/or have their milk rejected for collection. There has been no change to the meat withholding periods, so the change should not impact animal eligibility for slaughter.

The NZVA is aware that there are abamectin pour-on products still being sold and advertised as having a NIL milk withholding period. The distributors of these products are aware of the withholding period changes and are in the process of getting new labels approved by the Agricultural Compound and Veterinary Medicines (ACVM) team before they can update the labelling of each affected product. The NZVA has sought clarity on this situation from ACVM, which confirmed that nearly all products have been issued with new registrations as of 26 August 2022. All products will have updated labels and/or notifications of the withholding change distributed with their products in the near future.

ACVM advises that veterinarians to ensure farmers are aware of the change in MRL and product milk withholding periods. They strongly recommend discouraging farmers from using these products on their lactating cows from now on.