On any given day, approximately 1 million pigs are in transit on U.S. highways across all phases of the supply chain. As trailers move around the country between farms, transfer points and harvest facilities, the risk of pathogens traveling those same routes is an unavoidable reality.
“Each movement is necessary, but each movement presents risk,” says Dr. Christine Mainquist-Whigham, director of swine health at Pillen Family Farms/DNA Genetics.
After the porcine epidemic diarrhea virus (PEDV) epidemic taught the U.S. swine industry an important lesson, Pillen Family Farms/DNA Genetics implemented enhanced trailer sanitation by investing in washing, drying, dedicated fleets, transfer infrastructure and stronger lines of separation. That investment resulted in much fewer laterally spread PEDV introductions, Mainquist-Whigham points out.
“While those investments created a strong foundation, we recognized opportunities to reduce transportation-related biosecurity risk even further,” Mainquist-Whigham says. “We implemented dedicated truck washes and the use of transfer stations and segregated transportation assets, individually labeled trailers, GPS and geofencing technology across more than 200 sites and 450 vehicles, increased diagnostic testing procedures and cameras for proactive monitoring.”
Putting Eyes on the Fleet: Separation and Surveillance
By increasing and segregating its fleet, Mainquist-Whigham says the system reduced opportunities for pathogens to move between high-health, commercial, cull and market pig flows. Dedicated truck washes and the use of transfer stations helped keep high-health farms separated from transportation assets exposed to highly contaminated points of concentration such as markets and harvest facilities, while no-touch loading procedures limited driver movement and human traffic across established lines of separation.
In addition, the system also added requirements for washing or downtime before vehicles moved from lower-health to higher-health locations and established a dedicated transportation flow.
Mainquist-Whigham says these changes contributed to a nearly 50% reduction in transportation biosecurity compliance errors involving high-health herds, resulting in a post-implementation incident rate of less than 1%.
“Incorporating technology made transportation flow more visible and verifiable,” she says. “GPS, geofencing, cameras and remote auditing tools provided objective records of vehicle movement and helped identify errors before trailers reached farms. Rather than relying solely on written protocols, the system could monitor compliance and use the information to support continuous improvement and training opportunities.”
More Than Sanitation: Aligning Routes with Herd Health
Brock Pillen, co-CEO of Pillen Family Farms/DNA Genetics, says it’s important to understand that transportation biosecurity is about more than trailer sanitation.
“Our greatest gains came from creating systems that verify compliance, reduce opportunities for human error, and ensure transportation decisions align with herd health status,” Pillen says.
As disease surveillance becomes more aggressive, transportation decisions can be based on actual health status rather than assumptions, he adds. Monitoring for porcine reproductive and respiratory syndrome (PRRS), PEDV and other pathogens lets production systems adjust fleet assignments, routes, downtime requirements and sanitation resources based on the risk associated with each movement.
The U.S. pork industry has made tremendous progress in farm-level biosecurity, disease surveillance, and sanitation. But Pillen notes emerging research continues to reveal where transportation systems remain vulnerable.
Packing Plants: The Major Disease Convergence Point
A University of Minnesota research study led by Dr. Cesar Corzo and his graduate student Lucas Ferreira found PRRS virus in more than 50% of harvest plant dock samples. Researchers also found that 25% of trailers arriving PRRS-negative became contaminated during unloading.
Similar work evaluating multiple swine pathogens echoed these findings: contamination frequently increases during harvest plant unloading, highlighting the plant environment as a major disease convergence point and making transportation one of the industry’s most important and controllable biosecurity risks.
• Docks are the most contaminated samples.
• An important proportion of trailers arrived contaminated.
• The proportion of contaminated trailers increased after unloading market hogs.
• All samples tested negative for TGEV.
“Market hog and cull sow transportation trailer sanitation requires immediate attention given the high load of PRRSV, PEDV, porcine deltacoronavirus (PDCoV) and Senecavirus A (SVA) found in trailers leaving these points of concentration,” Corzo says. “Approximately 19% of the trailers arriving at the harvest plant had not gone through a truck wash prior to loading hogs at the farm; furthermore, 13% of the contaminated trailers at the plant will not go through a sanitation process before they load a new group of pigs.”
Iowa State University researchers have also demonstrated the value of thorough washing and disinfection. High-volume washing and power washing, when combined with disinfectant, significantly reduced PEDV contamination on livestock trailers. These findings reinforce effective washing and disinfection as the foundation of trailer sanitation, with many production systems adding detergent, inspection, disinfection, drying and Thermo-Assisted Drying and Decontamination, or TADD, as additional layers of protection.
A recent study led by Dr. Megan Hood with Reicks Veterinary Research and Consulting set out to assess a modified truck wash protocol, particularly in freezing temperatures in the winter months. Ultimately the study evaluated the risk of not performing a full drying procedure in the field and sampled trailers for the presence of PRRS, PEDV, transmissible gastroenteritis (TGE) and PDCoV. Results show the modified procedure works.
But Hood says it works with a caution. When she followed those trailers out of the truck wash 30 minutes later, almost half of the trailers had some frozen water on their surface.
“Even though we didn’t find any positives, that’s still a caution for producers that if they want to do this exact protocol, they may need to tweak it a little bit,” Hood says. “If there was virus on the trailer still and that disinfectant had frozen, then it would have stopped the action of the disinfectant and in theory, the virus could have survived.”
Biosecurity Doesn’t End at the Wash Bay
Transportation biosecurity remains critical to disease-control efforts, Mainquist-Whigham says.
“Harvest facilities bring together pigs from hundreds of farms representing multiple health statuses,” she adds. “Without effective sanitation, contamination acquired during unloading can be carried directly back into production systems.”
If the industry hopes to make meaningful progress toward PRRS and PEDV elimination, transportation biosecurity must remain a priority, Mainquist-Whigham urges.
“Transportation risk does not end when a clean trailer arrives at the farm,” she says. “Receiving animals remains one of the highest-risk transportation events within a production system. Even the strongest washing and disinfection program cannot compensate for inadequate source verification, diagnostic testing or isolation.”
Transportation represents one of the swine industry’s greatest remaining opportunities for disease prevention, Mainquist-Whigham says.
“Trailer sanitation is the foundation but additional safeguards such as fleet segregation, surveillance, transportation monitoring and controlled animal introductions provide important layers of protection when perfect sanitation cannot always be guaranteed,” she says.
