How to avoid heat stress in pigs

During the summer months, it is always a real challenge to minimize heat stress in your pigs. Especially now that heat waves seem to occur more often. Pigs that suffer from heat stress will perform less well. The feed conversion and growth of porkers will decline, and sows' milk production and fertility will decrease as well. 

The signals that indicate heat stress

Pigs have difficulty coping with high temperatures and rapid temperature changes. This can cause a lot of stress, especially in combination with a high relative humidity. Pigs do not have functional sweat glands and therefore cannot sweat as we humans do. Instead, they will stretch out on the floor and try to move as little as possible.

Several signs indicate heat stress. First, pay close attention to the pigs' breathing. As soon as they get too hot, they will start to breathe faster or pant to get rid of this excess heat. In addition, the pigs lie further apart and often on the grid instead of on the floor. They will also eat less, drink more, and show more aggressive (biting) behavior.

	Comfortable Normal behavior Normal activity Normal food and water intake Body temperature stable Respiratory rate 20-30/minute
	Heat stressed Lethargic Stretched out on the floor Decreased feed intake and increased water intake Body temperature increased Respiratory rate 40-50/minute
	Overheated No feed intake and greatly increased water intake Strongly elevated body temperature Respiratory rate up to 180/minute Blood circulation is disrupted

To prevent all this as much as possible, we have listed several tips for you:

#1. Ventilation

A rapid air movement around the pigs causes them to dissipate their heat faster. Therefore make sure that:

• There is sufficient ventilation capacity
• The air inlets, fans, and ducts are clean and functioning properly
• You prune any plants that pose a problem for proper ventilation
• Auxiliary fans are available for additional air exhausting and circulation
• You check the functioning of the cooling installation

#2. Cooling

Besides ventilation, there are several other methods to maintain the pigs' temperature and the house climate:

• Place sprinklers on the roof or in front of the air inlet (pay close attention to the humidity when using mist cooling)
• Spray the (concrete) floor inside and the pavement around the housing unit
• Switch off the piglet heating lamps during the day or only use them for the first 12 hours
• Spray the pigs 
• Open the doors in the early morning so the wind can blow through
• Run cold water through the underfloor heating (stop doing this 12 hours before the farrowing)
• Provide sufficient shade outside (organic)
• Paint the windows and the roof with white chalk

#3. Feed

As soon as the temperature starts to go up, pigs will eat less. If the temperature rises above 26°C, the feed intake will decrease with each increasing degree. How to handle this:

• Feed the pigs in the early morning or the evening when it is cooler
• If you feed the pigs more often, switch to smaller meals spread throughout the day
• Add some water to the dry feed
• Keep the feed as fresh, tasty, and hygienic as possible
• Add extra fat to the feed

#4. Drinking water

Pigs drink more when it is warm. This can be up to 6 times the amount they usually drink. That is why they must have sufficient clean and fresh drinking water available. So pay attention to the following points:

• Check whether the drinking water system is functioning properly
• Provide sufficient (thoroughly cleaned) drinking points
• Make sure the water flow is sufficient and keep a close eye on it
• Have the quality of the drinking water tested
• Add electrolytes and extra vitamins E and C to the drinking water if necessary (keep in mind that vitamin C only lasts 6 hours in a water solution)

#5. Activity

The more active a pig is, the higher its body temperature becomes. That's why they will move as little as possible. Keep an eye out for the following:

• Make sure it is quiet in the stables, so do not unnecessarily upset or move the pigs
• Postpone things like vaccinations or do this in the early morning
• Move farrowing sows to the farrowing pen earlier
• Make sure the pigs stand up to eat and drink
• Watch out for urinary tract infections. This can occur more often because they urinate less often when it is hot.

Observe daily

Keep a close eye on the behavior of your pigs. By closely observing your pigs daily, you can accurately determine your heat management and adjust it if necessary. A good house climate is crucial to prevent major problems and losses.