Air filter systems against PRRS and Mycoplasma

PRRS (Porcine Reproductive and Respiratory Syndrome) and Mycoplasma are two of the most costly diseases in pig farming. They lower resistance, cause growth retardation and lead to high costs due to medication and loss of production. A single air opening can be enough to allow infection to enter. Fortunately, a smart air filter system can keep this invisible enemy out.

Air filtration in SPF stables

Air filtration is standard in the strictest forms of SPF housing, where health status must be monitored extremely closely. However, not every SPF production company uses air filtration. Some rely primarily on strict biosecurity (hygiene locks, shower protocol, no animal contact, disinfection, strict transport rules). In areas with low pig density, this may be sufficient. However, more and more livestock farmers are discovering that air filter systems form a powerful barrier against these invisible threats.

By integrating the right filters into the ventilation system, the air remains clean and viruses and bacteria have less chance of entering the barn. But how exactly does this work, and what should you look out for when purchasing, using and maintaining filters?

How do PRRS and Mycoplasma spread?

PRRS and Mycoplasma often spread via small droplets and dust particles in the air. These aerosols can be carried tens of metres, sometimes even kilometres, by air currents. Without a barrier, contaminated air easily enters the barn. The consequences for the livestock are significant:

respiratory problems,
slower growth,
increased susceptibility to other infections

For the livestock farmer, this means higher costs, more work pressure and lower returns. That is why it is becoming increasingly clear that prevention through filtration is more effective and sustainable than treating with medication afterwards.

How does an air filter system work?

An air filtration system ensures that incoming air first passes through a filter that captures dust particles, bacteria and viruses. The live viruses in the moist air adhere to the filter, where they dry out and die, rendering them harmless.

A filter system in a barn always consists of two parts. The pre-filters remove larger dust particles, pollen and insects. This protects the finer filters from rapid contamination. Behind this is the fine dust filter which, depending on the type, blocks a large proportion of the bacteria or viruses. For extra protection of the filters, fly screen can also be used. This mainly protects the pre-filter from insects and foliage.

A filter system is also often combined with a cooling system. The cooler the air entering in summer, the fewer cubic metres need to be ventilated and therefore the filter surface area can be smaller. Pad cooling is best placed after the filter wall, but in practice you often see it in front of it. Pad cooling prevents insects and foliage from reaching the pre-filter. In that case, however, it is important to maintain sufficient distance between the pad cooling and the filter wall (1.5 – 2 metres). This gives free moisture more time to be absorbed by the air.

Effectiveness depends not only on the filter itself, but also on its placement. Filters in the air inlet are essential to prevent contaminated air from entering the barn. In addition, air flows must be controlled in such a way that there are no 'leaks' through which unfiltered air can enter.

What to look for when choosing a filtration system

An air filter system is custom-made, so always seek advice from experts. They know which system suits you best and can make an accurate calculation of the filter capacity. You also need to take into account the pressure drop in the barn; a filter always creates extra resistance, which means that fans have to work harder, leading to higher energy consumption. A filter system can easily increase the pressure drop by 35 to 50/60 Pa. Immediately after installing new filters, you must take into account the so-called initial resistance. Over time, the filters become dirty and the pressure drop increases further. Because the filters are part of a total ventilation system with or without pad cooling, air inlets and with or without central extraction, the total pressure drop can easily reach 100 or 200 Pascal.

In general, the more m3 that passes through the filter, the higher the pressure drop and the more energy you consume. We therefore often recommend installing approximately 15% extra filter capacity to relieve the ventilation system and reduce energy consumption. An additional advantage is that you are less likely to receive a ventilation alarm.

In some cases, high-pressure fans are required in a ventilation system with air filtration. These are special fans for situations with higher back pressures. These fans are characterised by very high air displacement with minimal energy consumption and noise production.

Choose the right filter

Seek advice on the type of filter that best suits your situation. Many filters are used in industry and civil engineering. However, the requirements here are less stringent than for capturing viruses in the agricultural sector. A good filter is one in which the fibreglass media is completely bonded to the filter frame. A good filter uses around 2.5 litres of adhesive and the frame consists of as few parts as possible. A good seal at the rear of the filter is also important for an airtight seal against the filter frame in which the main and pre-filter are enclosed.

Finally, leave the installation to qualified dealers who are well trained so that no damage is caused to the filter during installation.

Air filtration in existing stables

Many livestock farmers think that air filters are only possible in new buildings, but that is a misconception. Existing stables can often be adapted relatively easily. It is important that the ventilation capacity is maintained, as adding filters causes an additional pressure drop. If no additional ventilation capacity is added, less air will enter the barn. It is also advisable to opt for a positive pressure ventilation system, as air leaks do not pose a risk in this type of system. You can take this into account immediately in new buildings, but there are also options for renovation projects. Therefore, make sure you are well informed by our installers and experts.

Maintenance and monitoring

A filter that remains in place for too long can become mechanically damaged, but there is a more important problem: a clogged filter can lead to higher pressure drop, causing the capacity of your ventilation to decrease too much, resulting in an unhealthy climate in the barn. That is why maintenance is at least as important as the installation itself.

Replace the pre-filters regularly, at least once or twice a year. Replace the main filter every three to four years. Consistent maintenance ensures that the system remains highly effective and prevents ventilation alarms and unexpected problems. The connection to climate computers provides automatic monitoring, so you can be confident that you always have sufficient ventilation.

Conclusion: clean air, healthy animals

Clean air is the basis for healthy animals and profitable business operations. More and more livestock farmers are proving that air filters can keep PRRS and Mycoplasma out for years, even when neighbouring farms become infected. This shows that filtering not only works in theory, but also delivers major benefits in practice.

It requires an investment, but this pays for itself in healthier animals, lower medication costs and better production results.

What's more, filter technology is developing rapidly. Smart systems linked to climate computers and sensors make maintenance easier and allow effectiveness to be monitored constantly. In short: air filters are not an extra, but an essential part of modern stable hygiene and biosecurity. Choosing filtration means choosing peace of mind, certainty and future-proof livestock farming.

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