Why ventilation, biosecurity, and animal resilience all matter in the fight against PRRS

In this episode of The Real P3 Podcast, Casey Bradley sits down with Rob Langenhorst, technical sales manager with AAF International, at World Pork Expo to revisit one of the most persistent challenges in swine health: PRRS and the role of air filtration in reducing disease pressure. Rob shares how his background in microbiology shapes the way he follows PRRS virus evolution, especially the rapid changes seen in lineage 1C strains since 2021. As producers continue to face costly breaks, he explains why interest in air filtration has increased and why the goal is not always to eliminate risk completely, but to reduce the frequency and impact of disease events. The conversation breaks down the practical decision making behind filtered sow farms, including positive pressure versus negative pressure systems, ventilation requirements, barn age, exterior wall construction, ceiling and roof condition, and the many leak points that can affect system performance. Rob explains why there is no single answer for every farm and why the best filtration strategy depends on the structure, airflow needs, and production goals of each operation. Casey and Rob also clarify what makes animal agriculture filtration different from a standard home air filter. Rob explains how viruses are typically carried on dust particles, droplets, dander, and other transport vectors, and how properly designed filters help capture those particles before they enter the barn. The discussion expands beyond PRRS to include bacteria, influenza, HPAI, and the broader goal of providing cleaner air for pigs and people. A key segment of the episode focuses on research from the University of Minnesota using long term health monitoring data to compare filtered and unfiltered farms. Rob highlights reported PRRS break reductions of 58 percent in positive pressure farms and 51 percent in negative pressure farms, noting that both systems showed strong results and can help producers evaluate potential return on investment. The episode also explores the evolution of filtration options, from MERV 14 and MERV 16 filters to MERV 15, high flow MERV 16, Bio Shield filters, and 17 inch deep filters designed to improve airflow, protection, and project flexibility. Rob explains how these options can help producers protect pigs while balancing construction costs, airflow needs, and long term system performance. Beyond filtration itself, Casey and Rob discuss the layered nature of biosecurity. Air filtration is one important layer, but filtered barns can still break if other entry points are not controlled. The conversation touches on heated supply rooms, pressurized load chutes, shower protocols, UV boxes, feed bin risks, and the importance of consistent procedures every day of the year. Topics covered include: Why PRRS continues to challenge swine producers How lineage 1C strains have changed the conversation around disease prevention Why more producers are considering air filtration for sow farms Positive pressure versus negative pressure filtration systems How barn age, construction, and air leaks affect filtration decisions The difference between home air filters and animal agriculture filtration systems How viruses travel on dust, droplets, dander, and other particles What University of Minnesota data suggests about PRRS break reduction in filtered farms The potential return on investment from reducing PRRS breaks How MERV 15, high flow MERV 16, Bio Shield, and 17 inch filters fit into farm design Why clean air matters for both pigs and farm employees How filtration fits into a larger biosecurity program Why process, procedures, and daily consistency remain critical This episode is a great listen for swine producers, veterinarians, production managers, farm owners, biosecurity specialists, and anyone interested in practical strategies for reducing disease pressure, improving air quality, and protecting both pigs and people.