Whatever type of housing your pigs are in, the principles of ventilation are the same: Air goes in, air goes out. Sounds simple, but unfortunately it is not, especially with naturally ventilated buildings. 

Why is air movement so important?

  • Removes disease plumes in the air
  • Removes waste gases
  • Controls humidity
  • Controls temperature

What is ideal air movement?

As a general rule, one cubic meter of air should move in/out of the building, every hour, for every 1kg of pig in the airspace. However, the way the air moves around the building should also be considered. In the UK, the air outside naturally ventilated buildings is usually colder than the air already inside the building. This means when the air enters the building it will sink, and you don’t want cold air falling onto the laying area, you should have it falling where you want the pigs to dung. In naturally ventilated buildings we are relying on two things to encourage air movement.

1. The Stack Effect. This happens when air warmed by the body heat of pigs rises and leaves the building, normally through outlets in the roof; as it leaves it draws fresh air in through the side openings. 

2. Side to side air movement. The monopitch below show both side to side and stacking.

If you have naturally ventilated buildings, they should have been designed to use one of these air movement effects. But how can you tell if it is working correctly?

  1. Look at the pigs – Are they lying where they should? Are they dunging where they should? Are they dirty? Are they huddled? Are they tail or ear biting?
  2. Use your nose – Does the air smell fresh to you? Can you detect ammonia? If you don’t find the atmosphere pleasant, neither will the pigs.
  3. Start smoking! You can use smoke to see the way the air is moving. The traditional way is burning straw or newspaper over a barrow, but health and safety suggest a proper smoke machine is a better method! Is the air entering where it should? Is the air falling where it should? Is the air leaving where it should?

Ventilation is a tricky subject, but sometimes the smallest changes can make a big difference. Talk to your veterinarian or AHDB KT manager about investigating the ventilation in your building.

For further information, please see the product’s SPC or please contact your veterinary surgeon or Zoetis UK Limited, Walton Oaks, Dorking Road, Tadworth, Surrey KT20 7NS. www.zoetis.co.uk Customer Support: 0845 300 8034. Use medicines responsibly (www.noah.co.uk/responsible). Date of preparation: June 2017.