AASV news

AASV and NPB offer database to clarify Japanese MRL issue

In cooperation with the AASV’s Pharmaceutical Issues Committee, the National Pork Board’s Pork Checkoff has developed and will maintain a searchable database containing information supplied by pharmaceutical manufacturers providing recommendations regarding withdrawal times that comply with the new Japanese maximum residue limits (MRLs). The database can be accessed at the Pork Board’s Japanese MRL webpage.1 The database will be updated as new information is provided and contains an option that allows the reader to view the recent updates.

The AASV Pharmaceutical Issues Committee met during the Leman Swine Conference and developed a policy statement outlining recommendations regarding the use of antibiotics in the finishing herd and in breeding animals. This statement was approved by the AASV Board of Directors during their fall meeting.

The key recommendations put forth by the committee are as follows:

  • The withdrawal recommendations included in the database are based on information provided by the manufacturers of the specific products and apply only to those products, not to a drug class in general or to generic equivalents. It is recommended that you only use the specific products listed in the database during the finisher phase or in the breeding herd.
  • These recommendations assume product usage in accordance with the label directions. Extra-label use requires the administration of an extended withdrawal time and data may not be available to provide reliable withdrawal recommendations for specific products. It is the responsibility of the prescribing veterinarian to contact the manufacturer to obtain withdrawal guidelines for extra-label use.
  • Likewise, if a compound is administered via multiple routes simultaneously (eg, water and injectable), an extended withdrawal period may also be required. It is recommended that the veterinarian contact the manufacturer for specific product withdrawal recommendations.
  • In addition, it is recommended that veterinarians review the quality assurance practices in effect at the farm or within a production system to minimize the risk of mistakes in drug deliveries, storage, and administration.

The complete policy statement is available for review on the AASV website.2


1. Pork.org. Japan maximum residue limits (MRLs). Available at: http://www.pork.org/Producers/JapanMRL.aspx. Accessed November 2, 2006.

2. American Association of Swine Veterinarians. AASV recommendations to meet Japanese MRL requirements of US pork. Available at: http://www.aasv.org/aasv/position-japanMRL.html. Accessed November 2, 2006.

AASV board approves porcine circovirus position statement

At its fall meeting, the AASV Board of Directors approved a proposed name change and case definition involving porcine circovirus type 2 (PCV2). The Porcine Circovirus Ad Hoc Committee, formed by the AASV board at its 2006 annual meeting in Kansas City, proposed that the association adopt the name “porcine circovirus associated disease (PCVAD)” for the variety of clinical presentations currently described coincident with PCV2 infections. This was an attempt by the committee to recognize the variability in clinical signs currently associated with exposure to this virus in pigs. The board approved the motion.

In addition, the committee also proposed a formalized case definition to describe the minimum findings necessary to associate a given clinical presentation with exposure to PCV2. To derive this case definition, the committee elected to follow the methodology utilized by the Centers for Disease Control and Prevention (CDC) when describing the emergence of a previously unrecognized disease. The recommendation was also approved by the board.


Porcine circovirus associated disease (PCVAD) case definition

This case definition is considered to be a dynamic document which will be altered as additional information becomes available. The CDC model of describing the clinical expression of a new disease when a definitive diagnosis is not known was used in developing the format for the following case definition involving PCVAD.

PCVAD can be subclinical or include one or more of the following clinical manifestations concurrently:

  • Multisystemic disease with weight loss (formerly known as PMWS).
  • High mortality: doubling of historical mortality rate without introduction of a new known pathogen.
  • Respiratory signs, including pneumonia.
  • Porcine dermatitis and nephropathy syndrome (PDNS).
  • Enteric signs, including diarrhea and weight loss.
  • Reproductive disorders, including abortions, stillbirths, and fetal mummification (diagnosis requires the presence of fetal myocarditis associated with PCV2 antigen in lesions).

PCVAD is a broad categorization of multisystemic diseases that are confirmed by documentation of the following histopathological findings in affected pigs:

  • Depletion of lymphoid cells in lymphoid tissues of the growing pigs.
  • Disseminated granulomatous inflammation in one or more tissues (eg, spleen, thymus, intestine, lymph node [sternal, bronchial, inguinal, and mesenteric], lung, kidney, liver, tonsil).
  • Detection of PCV2 within the lesions of growing pigs.
  • Diagnosis of PCV2-associated reproductive disease requires the presence of PCV2 antigen in fetal myocarditis lesions.