Climate management in pig production

27 August 2020
3 minutes

The changing climate presents new challenges and opportunities for pork producers. There is a need to consider the productivity implications of climate change on businesses and the welfare of animals alike.  It is no surprise that most of us as pork producers have had an encounter in some way shape or form with ventilation.  Ventilation very often gets over complicated and misunderstood leaving the producer with no other choice but to rely on installation manuals and very confusing terminology.  If we take a step back briefly and think about what we are trying to achieve it may become slightly easier and if all else fails pay attention to the behaviour of the pigs!!

What is ventilation?

Ventilation is the displacement or movement of air inside the total space to provide ‘fresh’ air. The controlled airflow removes carbon dioxide (CO2), carbon monoxide (CO), ammonium (NH4), moisture, dust and brings in a fresh supply of oxygen (O2) to the pig house. The airflow also provides cooling.

How does it work?

The displacement of air to refresh the air in the pig house takes place by natural or mechanical ventilation. With natural ventilation, the wind outside has a significant impact and is often very hard to control or influence. The technical results are often lower, and management is more challenging with natural ventilation. With mechanical ventilation, you attempt to have no outside influences, to control the microclimate. Although this seems easy the controllers still have to be set and managed correctly to realise the return on the often-pricy investment.

Important features to consider with mechanical ventilation:

  • Create an intake of fresh air and outlet of air by ventilation systems.
  • Always ventilate consistently.
  • However, always ventilate as slowly as possible to prevent draught!
  • Check the minimum and maximum capacity of your ventilator to apply the correct settings.
  • Always prevent ‘pit’ ventilation.

This occurs when cold air falls in the manure channel or pit and flows along the to the animals, causing draught and moves bad gases from the manure pit to the animals.

Why should you ventilate?

In most pig units the animals are housed in specially designed buildings. This means you need effective ventilation to control the temperature (wind chill factor of the pigs) and air quality in the pig house. Ventilation systems are designed to maintain air quality (during cold weather) and to regulate temperature (during hot weather). The wind chill factor will largely depend on the outside temperature and humidity and this is controlled by ventilation. Gases and dust must be removed from the pig house and fresh air must enter the house.

If this is not done efficiently, accumulation of unwanted gasses, draught or poorly ventilated areas (dead spots) will impact negatively on the performance of your animals and lower return. The amount of air that needs to be moved depends on the level of CO2, heat and moisture that is produced by the animals, which is related to the number and weight of the pigs. Stocking density is important as this will have a direct influence on the ventilation strategy. As a guide, most genetic companies provide environmental targets and guidelines on the different stages of production and climate and or ventilation targets.  This does not take in to account the possible limitations that you may have in terms of housing or ventilating capabilities so they should be used only as a guide.


Minimum ventilation is the minimal refreshment of air needed to remove the bad gases, to remove the moisture produced by the pigs and to bring in the oxygen required by the pigs for breathing.

Key points to consider for MINIMUM ventilation

  • On the latest controllers, you can set the minimum ventilation in m³/hour.
  • The actual minimum ventilation in the unit can only be checked by measuring it with a special airflow measuring tool.
  • In older controllers, there is no link between percentage ventilation and actual ventilation in m³/hour.
  • Very often ventilation is set too high in winter and you may run the risk of causing a draught!
  • It’s important to understand the link between diameter and capacity of the ventilators. The diameter is an important parameter for the capacity of the ventilator!

ventilation is the maximum refreshment needed for pigs to avoid high temperatures and going into heat stress. If the maximum refreshment is higher than the calculated maximum ventilation required there is a risk of drought (speed of air too high). Previous norms suggest 1m³ / 1kg live weight however newer research suggests a norm slightly lower, depending on the ventilation system. De Heus together with a team of experts has equipped the technical specialist with innovative tools to help you calculate and check your ventilation norms.  It is suggested that the maximum is 80 or 60 m³/h, depending on the ventilation system that is used. For example, for finishing pigs it’s not 120 m³/h at 120kg live weight (older norm) but rather only 80 or 60 m³/h depending on the ventilation system that is used.

Key points to consider for MAXIMUM ventilation:

  • SLOWER IS BETTER, as this gives less risk of draught. The higher the ventilation, the faster the speed of the air and the higher the risk of a draught.
  • In summer, you don’t need to have a capacity larger than the maximum calculated ventilation, because extra refreshment isn’t necessary.


What are heating and cooling systems?

The main function of heating and cooling systems is to complement ventilation to maintain a comfortable, productive environment. Heating can be provided by simple gas/petrol/diesel heaters or by lamps on the piglet litter.

Cooling takes place by creating controlled airflow or by water (cooling/wet pads). The latter may be expensive and only efficient when a humidity controller is present. It is important to ensure that there is fresh air at the nose of the sow, especially in the farrowing room.


So, what can you do to help?


Pay attention to the behaviour of your animals:

  • Animals should be comfortable, quiet, spread out, sleeping on their side with legs stretched.
  • Pay attention to the health of the animals: colour/coat of hair/coughing/sneezing/diarrhoea etc.
  • Measure and monitor the feed and water intake of the animals.
  • Check the number of animal’s vs stocking density and the actual weight and maximum weight of animals in the pen.


  • Check the size of the ventilators and calculate the maximum capacity.
  • Check the minimum ventilation required.
  • Check the maximum ventilation required.
  • Turn off some of the ventilators if the capacity is too high (even in summer!), especially in the winter.
  • Ensure a good set-up of the desired temperature. In summer, this temperature will be a little higher and in winter a little lower.
  • Pay attention to the humidity; when it is too high, think about adding some more ventilation or heating.
  • Check whether the set temperature and ventilation values are the same as the actual values And if you are not sure, look at how the animals are behaving in the pen!

For more information regarding animal nutrition for Pigs please feel free to give our technical advisors a call.