Air contains always small solid and liquid partials, also known as dust. In relation to human health dust is often called fine dust. Dust particles in the air in pig stables contain a diversity of substances that can be harmful for the health of the farmer.
Particles with a diameter smaller than 10 μm (one hundredths of a millimetre) are able to deeply enter the respiratory system of human and animal. Both swine sector and the Dutch Government the desire to reduce the stable dust by reduction at the source.
In the stable dust is caused by three sources:
Known is that liquid feed reduces dust with 10 till 20 percent compared to dry feed. Furthermore, in dry feed the dust production increases when the pellets are softer. Meal feed causes the most dust. Spraying the pellets with fat reduces dust production with 40 percent compared to non-sprayed pellets.
Dried manure is a source for endotoxins. Pen soiling provides a lot of dust and is often caused by poor climate. Therefore it is important that manure rapidly exits the pen into the manure pit.
Dust originating from animals mainly contains skin cells and cannot be prevented. We do know that short haired pigs produce less dust compared to long haired pigs.
All three sources have an equal share in the amount of dust produced in stables. This has been showed through an earlier research done by Wageningen University and Research (report 654).
Limiting dust production through technique
In December 2012 Wageningen University and Research produced a report (654) about the functionality of different technical methods to reduce dust in a pig stable. The research showed than an oil nipple per pen would reduce the dust in the air with 62 percent. The yearly costs for this system were €5.30 per finishing place per year. Another method used was ionisation in which the dust received an electrical charge and therefor stuck to ceilings and walls. The dust in the air was reduced with 36 percent with this system. The yearly costs where over € 3 per finishing place per year. With the use of filtration of the air inside the farm, the dust could be reduced with 25 percent as well. This was done by filtering the total air content of the stable about 10 times per hour. Cost for this system where €7 per finishing place per year. Using one of these systems results in lower long abnormalities for the pigs.
There are possibilities to reduce the amount of dust in the air of pig stables, still it is not possible to reach a dust-free surrounding with the current knowledge. Reduction of the dust source and personal protection products offer the best protection.
A research from Stigas about dust load of different farm activities showed that treating pigs individually has the highest dust load. Also manually feeding pigs and cleaning pens with a high pressure cleaning device has a high dust load. Stigas advices to use personal protection products with a minimal P2-filter, or even a carbon-filter to reduce ammoniac intake as well. A dust-cap would not provide sufficient protection due to the chance of air leakage.