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“Do remove pig manure regularly as well as completely – and preferably remove the urine separately.” That, in short, is the recommendation given by researchers of Wageningen University & Research in the Netherlands.

Commissioned by the Netherlands Ministry of Agriculture, Nature and Food Quality, the researchers investigated measures that could be taken by pork producers to reduce emissions. Removing manure to a closed storage space can reduce pig house emissions considerably, they found. The report, called Measures at the source to reduce emissions from existing pig houses, was published only in Dutch.

This combination of manure-removing measures could lead to a considerable reduction in several types of emissions. Included are ammonia, odour as well as dust particle emissions.

Examples of successful approaches

A good example is the frequent and complete removal of manure using manure pits, manure gutters or manure shoves. This must be combined with clean floors as well as a specific dust reduction measure.

Another example would be to re-admit the thin fraction to the manure pit after having been exposed to air, in combination with clean floors and a specific dust reduction measure. This fraction will no longer generate any ammonia and odour emissions. It will therefore also reduce the same type of emissions from fresh manure.

Thirdly, cooling manure would also be a good measure to reduce emissions, the researchers wrote. At the moment, cooling the manure surface until approximately 15°C is already being applied in practice. The researchers, however, launched a plea to further reduce that temperature for all types of manure. To create a completely sustainable system using manure cooling, the removed heat could be used in piglet houses or adjacent living quarters.

Clean floors are a key condition

Having dirty floors could be a disturbing factor in the context of these measures, the researchers stated. Ammonia, odour and dust particle emissions will increase in this case. Clean floors are therefore a key condition in the fight against emissions at the source.

In addition, feed measures could lead to an extra emission reduction, predominantly to reduce ammonia and odour. The fine tuning of protein levels in feed, while keeping the needs of the (individual) pigs in mind, could generate an emission reduction.

Improving pig house air quality

Measures aimed at emission reduction at the source will also lead to an improvement in the air quality at animal level, the researchers wrote. In existing pig houses with air scrubbers, this can be achieved by increasing minimum levels of ventilation. This must be complemented with a certain type of reuse of heat, otherwise this type of energy use will be too high. – André Aarnink, Jos de Groot and Nico Ogink, Pig Progress