This article was written by Montse Torremorell of the University of Minnesota for the National Hog Farmer.
At the 2026 meeting of the American Association of Swine Veterinarians (AASV) I was given the task to present on biosecurity and what we need to do as an industry to “move the needle”. More specifically the ask was about presenting on biosecurity practices that we do, should do or should stop doing to control endemic diseases in pigs. This was not an easy task since the interplay between biosecurity and disease occurrence is complex.
Here are a few messages I shared.
First, we need to understand that with the advent of multi-site production we have added complexity and risk to the processes taking place in farms. There is no doubt that multi-site production has resulted in larger farms with more complex processes. The reality is that there is more of everything in these large systems, more people, more trucks, more supplies, more events and more processes. The number of events associated with practices that carry some degree of risk has increased significantly. For instance, let’s assume that the probability to introduce PRRSV through contaminated trailers is 1 in a 1,000. So, if a given trailer backs-up to a farm only once, the probability is low at 0.001%. If now the trailer backs-up to the farm weekly, in the course of a year the probability increases to 5% and if it backs up daily the probability increases to 30%. All the sudden the risk of introducing PRRSV via transport seems very possible. This is determined by the formula P = 1 – (1-p)n where (p) is risk of transmission and (n) is frequency of transmission. This tells us that a small chance becomes a big chance if it is repeated multiple times! In other words, we need to pay attention to events that happen frequently even if those events seem low risk. Examples of this are people, vehicles, feed and air.
In addition, the swine industry is an industry on wheels and those wheels move animals distances away. This contributed to having regions with high infection pressure and as a result, biosecurity practices that seem to work on some regions, they don’t in some others. Afterall, many biosecurity measures are “dose-dependent” and the disease burden put on those measures matters.
The word that comes to mind to move the needle on biosecurity is “intentionality”. We need to be intentional in our actions and our protocols. Decisions should be based on data, when data is available. For instance, data analysis supports the use of air filtration. Filtered farms have about 50% less PRRS outbreaks than non-filtered farms (MSHMP 2026). The data also indicates that trucks are easily contaminated at the processing plants during the unloading processes, which represents a risk back to the farms. More needs to be done on this area. However, data also indicates that in some instances, doing more doesn’t move the needle. We saw that with influenza where implementing strict handling of newborn litters in an influenza positive farms did not result in more pigs weaned influenza negative. However, when practices were combined with vaccination, more pigs were weaned influenza negative. Thus, we should strive to follow data-driven biosecurity decisions.
Our intentions should ensure that processes happen and we should question whether we have the right processes in place, or the processes are too complex or strained, and whether the processes are followed. Taking a “system thinking approach” to biosecurity should help setting the biosecurity measures for success. Unless we do so, we run the risk of falling in the “biosecurity fatigue” category.
A key point that is needed to move the biosecurity needle is to focus our efforts on the growing pig populations. Afterall, roughly 90% of the pigs are growing pigs and although it is important to have biosecurity in the sow farms, the sow population represents a small fraction of animals compared to growing pigs even though the impact of having infected sow farms is significant. Thus, weaning negative pigs combined with having effective biosecurity practices in growing pigs is key. Attention to dead animal removal, repairs and maintenance crews, and people and pig movement are just some examples of areas where better compliance is needed.
Traditionally the swine industry has focused effort on implementing biosecurity measures that help to keep viruses out. However, the opportunity today centers on implementing measures that help contain viruses within the infected populations. Whether that means to limit people’s chores to one site, or changing clothing and washing hands after visiting a site, or filtering the air out from infected facilities, we need to look at biocontainment practices with a fresh set of eyes.
Lastly, it does take a village to move the needle on biosecurity. The more participants implement measures with a common goal, the higher are the chances of having collective success. To do so will require determination, coordination, sharing of information and willingness to work together. Programs such as US SHIP and the National Swine Health Strategy coupled with technology, data integration and communication are key to bring all stakeholders together and move in the needle right direction.