MSU Extension Pork

Swine producers know that the risk of transmission for several diseases important in pig production typically increases as winter approaches; this is especially true for respiratory viruses including Porcine Respiratory and Reproductive Syndrome (PRRS) and Swine Influenza (SIV). Recent research showing transmission of PRRS1-4-4 (Lineage 1C variant), for example, begins to ramp up in late October and early November and should heighten our attention to farm biosecurity practices.

Biosecurity procedures are the first line of defense when protecting your swine herd from PRRS and many other diseases. Since transport vehicles are a possible source of PRRS transmission on farms, strictly enforced guidelines should be in place for cleaning, disinfecting, and drying vehicles used to transport pigs, including trucks and trailers returning from processing plants as well as other farms and buying stations.

Proper cleaning of trucks and trailers is necessary to maximize the level of protection from disease. Because PRRS and other important viruses can be spread by fecal matter and other body fluids from infected pigs, any organic matter left in the trailer has potential to spread virus. The first step in the line of defense against these diseases is to scrape/shovel bedding to remove manure thoroughly and then thoroughly wash your truck and trailer. This should be done a safe distance away from your swine site to minimize exposure of your pigs to dust/fomites and splashed or aerosolized organic matter from the truck.

Next, when power washing your trailer, the first stage is the use of a detergent to help remove all visible organic matter such as animal hair and manure on the trailer. Detergents aid both the process of organic removal and initiate the destruction of pathogens such as bacteria, virus, and parasites. Not seen by the human eye, a biofilm can develop over time which also harbors pathogens. For this purpose, using an acid solvent will help remove a biofilm layer.

As a trailer is washed, it is important to systematically break down the various surfaces. Be sure to wash the outside of the truck. Work from the roof downward along the side panels and finally the undercarriage. When cleaning inside the trailer, work front to back, beginning with the ceiling then downward along walls and then the floor. Any movable gates or ramps should be examined carefully after washing to ensure the entire area has been washed. A final rinse should be given to the entire truck and trailer to confirm that all visible organic matter has been removed.

After washing thoroughly, it is important to disinfect the inside of the trailer to ensure that all pathogens are destroyed including those suspended in biofilms on flat surfaces or trapped in small cracks/hinges or other concealed areas. When choosing a disinfectant, it is important to select one that has been established as effective against PRRS, SIV, PCV2, and PEDV. Many of the commercial disinfectants used in swine facilities are also effective when used in trucks, though controlled studies examining efficacy of disinfectants against PRRS 1-4-4, for example, are limited to a few products, including Virkon S, BioSentry-904, BipPhene, and Synergize. These products are most effectively and safely applied using a hydrafoamer, which allows for increased contact time and more thorough disinfection of the truck.

When using a disinfectant, it is important to follow all manufacturer’s safety recommendations, including use of protective gloves and eye/face protection. Use these products only in a well-ventilated area. Wash hands thoroughly after handling. Note: When using an ammonia-containing or acidic detergent during the cleaning process, you should avoid following it with a chlorinated disinfectant as a reaction may occur that can irritate membranes and cause breathing problems.

The third step that is highly recommended for cleaning of transportation vehicles is to remove moisture through proper drainage and thorough drying of the trailer. During Michigan winters, drying is best achieved using forced heated air, or baking, to help raise the temperature of the trailer interior and further destroy virus. The Iowa Center of Pork Excellence suggests that the inside of the trailer should be heated to above 150 degrees Fahrenheit for at least 10 minutes to effectively destroy viruses. While baking facilities for livestock trucks are not always available, producers can use industrial shop/space heaters to adequately heat the inside of the trailer. Though less effective than baking, allowing the trailer to completely dry following disinfection is also an effective practice. Raising the front end of the trailer (achievable by parking on a gradual slope) so that water runs out the back of the trailer and allowing air flow throughout the trailer are both useful practices to reduce drying time. Michigan State University Extension also suggests extending the time that the trailer sits empty and away from pigs to help inactivate the virus on a cleaned and disinfected trailer.

The fourth step in the cleaning process includes the cab, floor mats, and floorboards. All equipment, sorting boards, rattle paddles, as well as the undercarriage and wheels/tires should be washed, disinfected, and dried. Drivers should wash their hands (or apply hand sanitizer) and remove and properly dispose of plastic booties prior to entering the cleaned cab of their truck.

If you suspect a new outbreak of PRRS 1-4-4(1C) or any PRRS strain on your farm, it is important to contact your veterinarian right away. Your veterinarian can help with diagnostic procedures and is usually the best source for advice on selection of disinfectant, proper dilution rate, method of application, and effective duration of contact.

As the loss due to mortality and morbidity of a virus such as PRRS is costly and difficult to treat, consistent application of sound biosecurity practices, including transportation processes, are important tools for mitigating the risk of the disease entering your herd.