AASV Recommendations to Meet MRL Requirements of U.S. Pork

Background and Goals:

  • Protection of export markets and consumer confidence is of critical importance to the pork industry
  • Highest risk to these markets is from mass medication during the finishing period and in the breeding herd.
  • Animal care and production may require administering products during the finishing phase or in the breeding herd.
  • The AASV product withdrawal database contains only products for which the manufacturer has supplied specific MRL withdrawal information.  Products without specific MRL withdrawal information are not listed.


  • Use the best science available to ensure compliance with market specifications
  • If specific withdrawal times for a product have not been supplied by the manufacturer, the product will not be listed in the product/withdrawal database.  If a product is not listed in the database, the AASV recommends not using that product during the finisher phase or in breeding animals.  This includes proprietary and generic products.
    • A generic product may have a different withdrawal time than its proprietary equivalent. Follow the specific product withdrawal recommendation. 
  • Follow the recommended product withdrawal to meet the MRL requirements.  Product withdrawal time is based on applying the product at the labeled dosage and route and duration of administration.
  • If a compound is given by multiple routes of administration (example - given in the water, in the feed and/or by injection) simultaneously, withdrawal time may need to be extended.  Contacting the product manufacturer(s) about appropriate withdrawal time to meet market expectations is recommended.  
  • Follow appropriate administration techniques
    • Includes location of injection site
    • Includes volume of product within one injection site
    • Any change in location, administration, volume or labeled directions constitutes extralabel use. There may not be specific withdrawal data available for extralabel use of specific products.
  • Follow quality assurance procedures to prevent mistakes


Approved by the AASV Board of Directors on October 3, 2006


See the Pork Board's database of MRLs at: www.pork.org/mrl/