Heat stress – The hidden profit killer in modern pig production

Jørn Munch Madsen, Global Pig Nutrition Lead

In the Northern hemisphere we are getting closer to increasing spring-/summer temperatures. In recent years it has become clear that heat stress is a profit killer in modern pig production, however what is it and what to do about it? 

Heat stress occurs when environmental temperatures exceed an animal’s ability to maintain normal body temperature, disrupting the body’s ability to keep it’s internal “environment” stable. Most production animals have limited sweating capacity, making them biologically prone to overheating. When heat stressed, animals increase respiration rate and body temperature as their primary cooling response, (Springer, 2025). Feed intake typically decreases, leading to reduced growth performance and poorer feed efficiency, (Animals 2025, 15(6), 848; https://doi.org/10.3390/ani15060848). 

Heat stress in pig production 

Heat stress in pig production refers to the negative physiological and performance effects pigs experience when environmental temperatures exceed their ability to dissipate body heat. Pigs are especially vulnerable because they have few functional sweat glands and relatively limited thermoregulatory capacity. When dealing with high‑performing genetic lines selected for productivity the consequences of heat stress can be even more costly. 

Heat stress disrupts multiple body systems, as increased respiration rate & rectal temperature (panting as cooling response, respiratory alkalosis, oxidative stress, and altered metabolism). Gut integrity damage and higher oxidative load will impair nutrient absorption. 

Not only temperature should be taken into account when the focus is on heat stress. Humidity together with temperature impacts the animals well-being. 

How to mitigate heat stress? 

Modern mitigation involves both environmental and nutritional solutions: 

Environmental: Improved ventilation settings and cooling strategies. 

Nutritional: The technical performance of pigs in general caused by heat stress is regressive towards increasing temperatures and so is the economic outcome! 

In Vilomix we recommend the following actions when the target temperature exceeds 4o Celsius: 

Add ThermaCon® in pre-lactation and lactation diets as well as from 25 kg live weight until slaughter 

Consult your Vilomix nutritionist to deploy additional actions as: 

• Including ThermaCon®  in your nutritional program 
• Increasing nutrient density pr kg feed 
• Low-protein diets supplemented with synthetic amino acids improve growth, gut health, and oxidative balance under heat stress 
• Lowering fiber to reduce incremental heat production 
• Feeding strategies that reduce heat increment 
• Supplements with betaine, additional vitamins, electrolytes, antioxidants etc.