Opinion: The Veterinarian's Role in Residue Avoidance

August 2, 2006 — Bernie Curran, Steve Henry, Jim McKean, David Reeves, John Waddell

Failure of the U.S. pork industry to understand and comply with changes in the Maximum Residue Limits (MRLs) recently announced by the Japanese Government poses a clear risk to the U.S. pork industry's export market. Producers and veterinarians should not underestimate the significance of these changes because exports add approximately $8 in value to every hog marketed in the U.S. As USMEF CEO Phil Seng says, "... just one out-of-compliance animal could put this strategic market at risk." We are writing this opinion to encourage veterinarians across the country to be aware of the circumstances surrounding this issue, to implement guidance recommendations concerning withdrawal times that will meet market expectations, and to work with producers and packers in assuring compliance.

Unless there is specific, packer-verified knowledge that no part of the pigs will be going to the Japanese export market, we believe that all product should be produced as if it is intended for export. This recognizes that considerable pork product is exported through 3rd party distributors and/or further processors. Included are products from finishing pigs and sows, both muscle and organ tissues. Our concern is that not all producers and packers are aware of the significance of this issue and we believe swine veterinarians should lead educational efforts.

It is our opinion that veterinarians should update their withdrawal time recommendations following pharmaceutical company guidelines for Japanese pork product, not U.S. product. Animal health product specific information can be found on the National Pork Board's web site at http://www.pork.org/Producers/JapanMRL.aspx#7. Keep in mind that this guidance estimates the clearance rate as determined in healthy animals. If the animals are sick or compromised then the withdrawal times may need to be extended. Remember also that pharmaceutical company guidance assumes that products are given in dosages and by routes as labeled. Failure to follow label directions for dose, duration of treatment, and amount administered per site may each result in longer withdrawal times. If there is a difference between various company recommendations for a given product, then we suggest that it is prudent to implement the longer withdrawal time.

We also suggest the following:

1. Revisit the use of pharmaceutical products on all farms and eliminate those counter-indicated or marginally indicated.
2. Make health and management changes that reduce the need for pharmaceutical use particularly in late finishing and in sows. This may include changes in pig flow, ventilation, husbandry, and/or vaccination protocols as examples.
3. Restrict drug use in an extra-label manner and ensure that any extra-label use is in compliance with the guidelines set forth in AMDUCA (http://www.fda.gov/cvm/s340.htm). Remember, AMDUCA gives the veterinarian the responsibility to ensure that an adequate withdrawal time is communicated. It is the veterinarian's responsibility to communicate withdrawal times with regard to not only the U.S. standards but also the Japanese MRL standards.
4. Encourage feed manufacturers to follow Good Manufacturing Practices (GMP). As an example, some producers are adding dye to medicated feed to track its use and assure that delivery is accurate. This helps overcome errors associated with feed delivery. Others have instituted mill audits and still others prohibit the use of in-feed pharmaceuticals in the last weeks of finishing.
5. Treated animals should be identified and the date of the treatment recorded. If an individual within a group is treated, it should be removed from the population and marketed only after the appropriate withdrawal time. Some veterinarians and producers have placed central systematic control on the use of injectable pharmaceuticals and others are prohibiting the use of injectable pharmaceuticals unless absolutely necessary to treat or control disease in the last weeks of finishing.
6. Follow approved label directions and adhere to the withdrawal times provided by the manufacturer to meet MRLs. This is the surest way to assure efficacy and safety. However, current U.S. labels do not necessarily meet MRLs established by Japan and must be adjusted accordingly.
7. Examine the need for therapy and also consider how both the treatment and the treatment process contribute to the risk of violative residues. Determine if the process is controllable and repeatable. Ask, "What is the potential for human error in the process?" "Is the process both precise and accurate?" For example, in some cases continuous feeding of therapeutics can add considerable risk and thus should be avoided in favor of pulse treatment or water medication. In other cases, continuous feeding may be preferred. We consider the following to be either high risk and/or marginally effective treatment processes:
   1. Use of late-term finishing treatments.
   2. Use of products with extended withdrawal times, particularly in late finishing pigs and in sows.
   3. Routine systematic administration of therapeutics without a substantive diagnosis. For example, the routine administration of antibiotics to sows peri-partum is highly discouraged.
   4. Administration of antibiotics in cases of uncomplicated viral disease e.g., influenza.
   5. Use of growth promoting antibiotics in high health pigs.
   6. Use of growth promoting antibiotics in late finishing pigs.
   7. Use of feed additive antibiotics for the treatment of sick pigs.
   8. Use of feed additive antibiotics when water medication is equally effective.

We encourage our colleagues to take all barn personnel through a complete review of the Pork Quality Assurance Program and the Take Care, Use Antibiotics Responsibly Program promoted by the National Pork Board and AASV emphasizing the significance of compliance. Make non-AASV veterinarians aware of this issue and provide them information through local and state veterinary associations. We further encourage you to make producers aware of the issue, provide accurate guidance to producers and veterinarians alike, and determine if compliance is a problem within farms and systems that you work with.

There are two points of vulnerability on this issue. One is with the unaware and/or unmotivated. The second lies in the potential for human error or accidental contamination. You can help by providing leadership on this issue. For more information on this matter visit www.pork.org or www.aasv.org. Thanks for your leadership and service to the pork industry through veterinary medicine.

[Ed. Your thoughts regarding this, or any e-Letter article, are always welcome at comments@aasv.org.]

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Bernie Curran, Steve Henry, Jim McKean, David Reeves, John Waddell -- five past presidents of AASV