Climate change significantly increases the risk of heat stress in livestock in the Netherlands. Summers are becoming hotter and longer, causing dairy cows, pigs, and poultry to be exposed more frequently to temperatures that exceed their physiological limits. This article answers the most important questions about how heat affects livestock, how to recognize the symptoms, and what you, as a livestock producer, can do to mitigate the effects.
What makes Dutch livestock farms particularly vulnerable to heat?
Dutch livestock farms are particularly vulnerable to heat stress due to a combination of high stocking densities, enclosed housing systems, and the increasing frequency of heat waves. Many barns were built for a temperate climate and lack adequate ventilation or cooling for extreme temperatures. In addition, a relatively large number of high-yielding livestock breeds are raised in the Netherlands, which naturally produce more body heat.
Dairy cows with high milk production generate more metabolic heat than low-producing animals. The more a cow produces, the more sensitive she is to heat. The same applies to fast-growing broiler chickens and hyperprolific sows: animals that are genetically optimized for performance react more strongly to thermal stress.
Infrastructure also plays a role. Many Dutch livestock farms use closed or semi-open barns where air circulation is limited. On hot, windless days, the perceived temperature inside the barn quickly rises above the animals’ comfort zone. Combined with high humidity—which is common in the Netherlands—this leads to a high Temperature Humidity Index (THI), the metric that indicates when heat stress occurs in livestock.
How does heat stress affect livestock production and health?
Heat stress in livestock directly leads to reduced feed intake, lower production, and increased susceptibility to disease. When an animal can no longer adequately regulate its body temperature, its energy shifts from production to thermoregulation. This has measurable consequences for milk yield, growth, reproduction, and gut health.
In dairy cows, milk production begins to decline when the THI exceeds 68. At the same time, feed intake decreases, rumen function deteriorates, and the risk of abomasal torsion and ketosis increases. In sows, heat stress during gestation leads to more premature births, lower birth weights, and reduced colostrum production. Finishing pigs grow more slowly, have a higher feed conversion ratio, and exhibit more carcass fat at the expense of lean meat.
Poultry are particularly vulnerable because chickens cannot sweat. They cool themselves by panting, which leads to a loss of carbon dioxide and an imbalance in the acid-base balance. This results in weaker eggshell strength in laying hens and lower breast muscle yield in broilers. The intestinal barrier is also compromised in hot weather: the permeability of the intestinal wall increases, which raises the risk of infections.
What symptoms indicate heat stress in cows, pigs, and poultry?
The symptoms of heat stress in livestock vary by species, but are easily recognizable in practice. Rapid breathing, reduced feed intake, and lethargy are the most common signs. Early intervention is crucial, as chronic heat stress has long-term consequences for production and health.
Symptoms in cows
- Increased respiratory rate (more than 60 breaths per minute)
- Drooling and panting
- Reduced feed intake and increased water intake
- Decline in milk production and changes in milk composition
- Spending more time standing in the barn (less time lying down)
- Fertility problems: reduced fertility and lower conception rates
Symptoms in pigs and poultry
- Pigs: panting, reddened skin, reduced appetite, increased water intake, slower growth rate, and, in sows, fewer piglets per litter
- Poultry: open-beak panting, wings spread away from the body, wet droppings, reduced egg production in laying hens, higher mortality rates during extreme heat
Also watch for indirect signs, such as an increase in wet litter in poultry houses or a rise in the number of birds that are not going to the feeder. These are early indicators that give you the opportunity to take action before production losses occur.
How can heat stress in livestock be reduced or prevented?
Preventing heat stress in livestock requires a combination of barn management, climate control, and dietary adjustments. No single measure is sufficient on its own, but together they form an effective system for limiting the thermal stress on animals.
The following measures have proven effective in Dutch practice:
- Improving ventilation: Ensure adequate airflow in the barn, preferably through mechanical ventilation or tunnel ventilation. Aim fans at the animals, not at the feed trough.
- Implement cooling measures: Mist systems or drip cooling on the cows’ backs effectively lower the perceived temperature. Always combine this with additional ventilation to promote evaporation.
- Adjust feeding times: Feed the majority of the ration during the cooler morning and evening hours. This reduces the peak load on rumen fermentation during the hottest parts of the day.
- Ensure a steady water supply: Provide plenty of drinking stations and cold, fresh water. Water intake increases significantly in hot weather and is the animal’s first line of defense.
- Providing shade: During heat waves, shade structures or access to the barn are essential for grazing.
Prevention starts even before summer. Check ventilation systems in the spring, adjust feed rations in a timely manner, and monitor the THI daily as soon as temperatures rise.
What role does nutrition play in managing heat stress?
Nutrition plays a key role in managing heat stress in livestock. Certain nutrients support osmotic balance in cells, protect the intestinal barrier, and help animals better cope with the physiological effects of heat. Betaine is one of the most scientifically substantiated ingredients in this regard.
Betaine acts as an osmolyt: it helps cells retain water and protects them from dehydration and shrinkage at high ambient temperatures. This is particularly relevant for the intestinal wall, which becomes more vulnerable under heat stress. Research shows that betaine enhances the expression of tight junction proteins such as occludin and claudin-1, thereby keeping the intestinal barrier intact. In addition, betaine reduces oxidative stress and has an anti-inflammatory effect.
For poultry, there is specific evidence that betaine improves breast muscle weight under heat stress through enhanced cellular hydration and antioxidant protection. In pigs, it contributes to better heat tolerance and maintenance of intestinal health. In dairy cows, betaine supports osmotic regulation in the rumen and can help maintain dry matter intake, even when animals have a reduced appetite due to heat.
In addition to betaine , feed and drinking water additives such as organic acids and electrolytes are also important. During heat stress, drinking water is a particularly effective delivery vehicle for nutrients: water intake remains reliably high, even when feed intake decreases.
How will climate change further exacerbate heat stress in the Netherlands?
Climate change will structurally exacerbate heat stress in livestock in the Netherlands. Forecasts indicate longer and more intense heat waves, higher average summer temperatures, and more tropical nights during which the temperature no longer drops enough to allow for recovery. This means that heat stress is evolving from a seasonal problem into a chronic business risk.
What this means in practical terms for livestock farmers:
- More days per year above the critical THI threshold for dairy cows, pigs, and poultry
- Shorter recovery periods at night, leading to increased cumulative stress
- Greater impact on reproductive outcomes during the summer months
- Higher risk of secondary health problems due to a weakened immune system
- Increasing pressure on barn systems that are not designed for extreme heat
Livestock farmers who invest now in climate-resilient barns, adapted feeding strategies, and preventive health programs are gaining a head start. Waiting until a heat wave strikes is a costly strategy: production losses during and after a heat wave are significant, and recovery takes weeks to months.
Internationally, there are regions where heat stress has been a chronic problem for decades, such as the Middle East and Southeast Asia. The approaches that have proven effective there—including dietary supplements based on betaine as an osmolyt—are now becoming increasingly relevant for Dutch livestock farming as well.
How Jodoco helps with heat stress in livestock
At Jodoco, we develop scientifically backed feed and drinking water products specifically designed to reduce heat stress in livestock. Our approach combines multiple mechanisms of action into a single formula, ensuring that animals continue to function optimally even under thermal stress.
What we offer for heat stress management:
- Osmotic protection: Our products, which are based on natural betaine, help cells retain water and protect the intestinal barrier in hot weather
- Improved intestinal integrity: By strengthening tight junction proteins, the intestinal wall remains intact, even when heat stress increases permeability
- Flexible administration: Via drinking water or feed, depending on the situation at the farm
- Proven effectiveness: Backed by trials conducted at ILVO Ghent and Schothorst Feed Research, among others
- Tailored Solutions for Every Animal Species: Specific solutions for poultry, swine, and ruminants, such as Jodobet and Jodoplume
Climate change is making heat stress management increasingly urgent for Dutch livestock farmers. We’d be happy to work with you to develop a strategy tailored to your farm and the type of livestock you raise. Please contact us for personalized advice or a product demonstration.
