<%@LANGUAGE="JavaScript1.3"%> Swine Health Management - Air

Environmental effects Thermal control
Building requirements - insulation
Temperature requirements Cooling requirements

Cooling Systems

When to cool? Cooling is essential to help pigs cope with heat stress. All pigs can die from heat stress, especially after bullying.
Breeding boars
>24 degrees C
Semen production can be significantly affected for 6 weeks if the boars are subjected to >30 degrees C for more than 2 days.
Farrowing sows
>24 degrees C
Live births are reduced and stillbirths increase as sows are fatigued.
Lactating sows
>24 degrees C
Heat stress reduces milking capacity and feed intake, which affects weaning weights and increases weaning to service interval. Not eating can result in excess maternal weight loss.
Gestating sows
>24 degrees C
Inadequate intake and increased stress levels result in reduced farrowing rate, birth weights and litter size.
finishing pigs
>22 degrees C
Feed intake and FCR significantly negatively affected by heat. Cooling helps to keep pigs clean and reduces disease particularly of the digestive and respiratory tracts.


How to cool and when:
Farrowing house drip cooling:
  • Suspend drip cooler 30 cm (12 inches) from top of crate.
  • Discharge on to the sow's neck and shoulder area. It should be located far enough back so there is no chance of getting water in the sows ear while lying down.
  • Ensure the sow cannot reach the nozzle with her mouth.
  • Run system so that the floor does not get wet. The system should run only long enough to produce minimal run off from the sow's body. This is particularly important when solid farrowing floors are used.
Suggested cooling times
degrees Celsius On (minutes) Off (minutes)
24-28 1 20
28-30 2 10
30-32 3 5
32+ 4 5
Spray cool installation:
  • Mount the spray nozzles over the dunging area of the pen. Locate one per pen at a height to produce a spray pattern large enough in diameter to cover the required area. Need to produce a coarse droplet spray not a fine mist of fog.
  • Suggested use 1-3 minutes on and 15-30 minutes off. The optimum temperature at which to begin spray-cooling pigs depends on the age, size of animals and number of pigs in the pens.
  • Aim to wet all the animals in the pen and then turn off the system to allow the water to evaporate from their skin before restarting. Need to vary on and off intervals according to ambient air temperatures, humidity and behaviour of the pigs.
Dung Training:
  • The cooling system can be used to assist in dung training.
  • Use the system for 2 minutes on and 60 minutes off for the 1st 2-3 days upon entry.
Wallow maintenance:
  • Ideally allow wallow to run dry once during the summer and start a new wallow to help control leptospirosis.
  • Ensure wallows do not collect large rocks and other sharp objects which can damage legs in unsuspecting pigs.
  • Do not use water supply as a wallow.
  • On very sandy soil it may be necessary to build a wallow from soil and clay.
Evaporative Cooling:
While evaporative cooling can help to significantly reduce the room temperatures and are ideal in boar studs. They need maintenance and looking after.
  • Ensure nozzles are cleaned at each all-in/all-out.
  • Check for evidence of clogging with lime - commercial household de-mineralized solutions can be used. Do not use strong acids or metal pins to unclog blocked nozzles.
  • Check spray system is not spraying in feeders.
  • Ensure floor is not becoming too wet.
  • Observe each nozzle when spraying and ensure water is being diverted to the correct location on the animals.
  • Check for leaks at the fittings daily.
  • If a controller is used, ensure the controller works within expected operating parameters at least quarterly.
  • Check floors are not becoming too polished and remain wet.
  • Clean water fitters as required, minimum 4 times a year.
  • Ensure in winter time the system is protected from freezing.
  • Ensure evaporative cooling system has no holes in it.
  • Check for rodent damage to cooling system.


Alarms and safety mechanisms:
  • Under regulations where the pigs have automatic ventilation systems alarms and fail safes must be fitted.
  • These should be checked daily and audited weekly


Problems if cooling system improperly used:
Farrowing house
Wet farrowing floors can increase scour problems. Sows may slip on damp floors.
Boar/gestation Floors may become slippery if pigs remain wet. At breeding animals can be injured if they slip on the wet floor. They can over cool and result in abortions.
Grow/finish Wet pigs, which are over cooled, particularly if high ventilation rate may lead to increased stress.
Spray/not spraying
If spray-cooling system sprays into the feeders this can block feeders. If they spray on the walls this can damage insulation.
Storage tank position Note: hot water does not provide cooling. Ensure main storage tanks are properly placed and not subjected to direct sunlight
Humidity effects High humidity can interfere with evaporative cooling.