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Top tips on tackling heat stress in outdoor and indoor pigs
With prolonged warm spells becoming the norm, heat stress in pigs is an increasing problem. From around 18oC upwards, sows and finishing pigs begin to suffer and with their inability to sweat and relatively small lungs, heat stress can cause substantial economic losses.
Finishing pigs can demonstrate a change in feeding behaviour and reduce feed intake by as much as 500g per day when they are suffering from heat stress. And for sows, it has a significant impact on both feed intake and fertility.
Mark McFarland, feed additive product manager from Lallemand Animal Nutrition provides some practical advice on how to manage heat stress by focusing on the sows’ environment, behaviour and nutrition.
Signs of heat stress
A temperature sensor is useful to have both inside and outside the building, and it is important to know what to look out for. Key signs of heat stress in pigs include:
- Panting and higher heart rate
- Unusual feeding behaviour such as less frequent feeding and gorging (leading to bloat)
- Reduced overall feed intake, which will also be reflected in the growth curve
- Increased water consumption
- Skin can look drier and paler if pigs become dehydrated
- Inaction or wanting to lie down
Adjusting the environment to tackle heat stress
Preparation and early preventative action are key to managing the risk of heat stress, highlights Mr McFarland.
To keep pigs cooler outdoors:
- Make sure that arks or tents are properly insulated, or white in colour to reflect the heat
- Provide adequate shade
- Clean fresh drinking water is essential
- Create mud wallows to keep pigs cool and provide a form of sunscreen
There is a greater level of control in indoor herds, however there are still things producers can do to prevent heat stress compromising performance, including:
- Provide adequate ventilation and ensure systems are in good working order. Automated systems will adjust air inlets and fans according to conditions
- Evaporative cooling/misting systems or sprinklers can also help
- Make sure pigs have a constant supply of cool, clean water, maintaining adequate pressure during peak demand periods
Adjusting dry rations to prevent heat stress
Modifying the diet can help to prevent the reduced feed intake which is commonly seen in pigs suffering from heat stress.
When comparing dry to liquid feed, Mr McFarland explains that reduced intakes and performance tends to be associated more with dry feed.
However, there are things producers can do to offset this:
- Nutritionists can alter the energy levels of the feed by reducing the fibre and protein content, as these two nutrients require a high metabolic rate in digestion during periods of heat stress
- When reducing protein content, it is important to make sure amino acid levels remain sufficient
- Provide food late at night or early in the morning to avoid a drop in feed intake, as pigs will eat more as temperatures drop off
- Use a specific probiotic live yeast such as Levucell SB to help regulate feed intake, digestion and performance. Supplementing the diet with this probiotic yeast is proven to stabilise feed consumption and the total time spent eating
Managing heat stress in pigs
Hannah Elliott, monogastric technical manager at Lallemand Animal Nutrition, explains: “Heat stress can have a significant impact on all ages of pigs with research showing that they start to show signs of heat stress from as low as 17-18oC. However, by paying close attention to the pig’s nutrition and environment, heat stress can be effectively managed.”
Ms Elliott explains they have seen good results in maintaining feed intakes when pigs have been given probiotic supplementation in their diet, mainly in their ability to adapt their eating behaviour to the heat stress conditions.
“We’ve found that when using the specific probiotic live yeast, Saccharomyces c. boulardii CNCM I-1079 (Levucell SB), normal feeding behaviour, feed intake and growth in fattening pigs can all be maintained during a significant heat stress period.
“We also have positive field experience using the probiotic to ensure sow performance under heat stress, with improved piglet growth during lactation and at weaning.”
It is not just about what is in the feed, adds Ms Elliott, but also when and if the pig consumes it.
“It’s far better to feed sows during the cooler periods of the day as they will be likely to consume more. Smaller portions fed regularly throughout the day, can also help avoid a decrease in feed consumption and reduce feed spoilage,” she says.
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Contact UsPublished Jan 8, 2025 | Updated Apr 9, 2025