Time to focus on wean-to-market biosecurity

Researchers attempting to understand the rate of disease transmission in growing pigs.

November 2, 2021

3 Min Read
Pen of weaned piglets
National Pork Board

Wean-to-market farms continue to serve as a reservoir for diseases such as porcine reproductive and respiratory syndrome virus (PRRSV) and porcine coronaviruses such as porcine epidemic diarrhea virus (PEDV) and porcine delta coronavirus (PDCoV.) The October 2021 Swine Disease Reporting System indicates that over 31% of samples tested in the wean-to-market phase are positive for PRRSV, 8.8% for PEDV, and 0.7% for PDCoV1.

Evidence from the field also indicates that disease introduction occurs at a high rate in pig dense areas. Current work at Iowa State University is attempting to understand the rate of disease transmission in growing pigs and associate the timing of disease introduction with farm biosecurity characteristics or events that could cause those disease introductions.

An ongoing case control study in northwest Iowa to detect the introduction of wild-type PRRS, PEDV, and PDCoV, into groups of growing pigs indicates that the incidence of disease introduction is high. Seventy-five groups of growing pigs that were negative at placement for PRRSV, PEDV, and PDCoV are being followed and results indicate that 97% of groups have become positive for PRRS, 15% for PEDV, and 26% for PDCoV. Other studies following growing pigs have also shown high incidence of wild type PRRSV introduction at 44% (Angulo, 20192) and 91% (Moura, 20213.)

The cost per pig that is placed negative for PRRSV and becomes positive for PRRSV prior to market is estimated at $2.29 due to increased mortality and slower growth4, yet most of the swine industry’s focus on disease prevention through biosecurity is focused at the sow farm level. The results of these studies show that there is much opportunity to improve disease prevention and gain through biosecurity in the wean-to-market phase of production.

While we are still learning and trying to understand the most common routes for disease introduction into wean-to-market farms, there is still opportunity to utilize what we already know about PRRSV and coronavirus transmission to help improve biosecurity. The creation and implementation of Secure Pork Supply Plans for growing pig sites can help improve facility biosecurity.

It is important to review all aspects of your operation that could result in pathogen spread, including caretaker movements between farm and farm entry protocols, management personnel entry, visitor entry, contract crew labor entry, maintenance personnel and equipment entry, feed delivery, animal movements and transportation, supply delivery, carcass disposal, garbage disposal, lawn care and snow removal, and manure removal. Working with your veterinarian to identify gaps in biosecurity in these areas and protocols to help address vulnerabilities to disease introduction is an important step to start improving a farm’s biosecurity. Educating and training employees and contractors about the importance of biosecurity and how to implement biosecurity practices is critical for a farm’s biosecurity plan to be implemented.

A robust biosecurity culture and plan takes time to build and execute correctly. By focusing on biosecurity now in the wean-to-market phase, producers can help limit spread and reduce the costs of disease like PRRSV, PEDV, an PDCoV as well as be prepared to combat the introduction or spread of other emerging or foreign animal diseases.

Sources: Kate Dion, Iowa State University, who are solely responsible for the information provided, and wholly own the information. Informa Business Media and all its subsidiaries are not responsible for any of the content contained in this information asset.


  1. Trevisan, G., Linhares, D., 2021. Swine Disease Reporting System (Report 44). https://www.swinehealth.org/domestic-disease-surveillance-reports/

  2. Angulo, J. Incidence and dynamics of wild type PRRS virus in growing pigs from Midwest U.S. farms. Leman Conference Proceedings, 2019. pp1.

  3. Moura CAA, Philips R, Silva GS, Ramirez A, Gauger PC, Holtkamp DJ, Linhares DCL. 2021. Association of wild-type PRRSV detection patterns with mortality of MLV-vaccinated growing pig groups. Prev Vet Med. 189:1-7.

  4. Holtkamp D.J., Kliebenstein J.B., Neumann E.J., Zimmerman J.J., Rotto H., Yoder T.K., Wang C., Yeske P., Mowrer C. Haley C. 2013. Assessment of the economic impact of porcine reproductive and respiratory syndrome virus on United States pork producers. J Swine Health Prod. 21(2):72-84.

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