Air conditioning in the barn: How to make summer bearable

A suitable climate is essential in a dairy cow barn. Especially in summer, more attention needs to be paid to maintaining correct temperature and humidity levels in the barn as a high THI value (Temperature Humidity Index) can often lead to heat stress in your herd in warmer months.

In the following article, we talk about ways to cool the air in the barn and about what to take into consideration when choosing a specific system or method for cooling.

What are the optimum climate conditions in the barn for dairy cows?

The optimum air temperature for cattle is between 4 ° C and 15 ° C. The animals feel most comfortable and also perform the best within this temperature range. Relative humidity should be in the range of 50% to 80%. Air movement in combination with the air temperature has a decisive influence on how cows can handle heat as well as cold. In summer, proper air movement is important to prevent heat accumulation and keep the animals cool. Evaporative cooling can be promoted, for example, by ensuring slight air movement.

However, it is important to avoid drafts in the barn. Freedom to move is especially important in the resting area as animals need to be able to protect themselves from drafts.[2]

Why is air conditioning in the dairy cattle so important?

The high temperatures and heat periods in the summer months represent a major burden for cows. Originally cattle come from the cold climate zone and are therefore less heat resistant. At high outside temperatures (above 30 ° C) and a relative humidity of 35% to 50%, dairy cows already have a massive increase in internal body temperature as well as surface temperature. That means they are suffering from heat stress. [1]

Heat stress can cause serious problems and affect animal health as well as performance. Therefore, attention should be paid to efficient ventilation, cooling and increased air movement in the barn.

Types of air conditioning and systems for keeping cows cool


Fans increase the air speed in the barn and the air flow generated helps the animals during the heat release process. It should be noted that an air speed of minimum 2 m/ s on the animal is necessary. Be careful to avoid drafts!

When the environment is dry, a speed of 5 m/s is a problem for animals. [3]

In poorly ventilated barns, fans can reduce relative humidity and improve air quality. In well ventilated barns, on the other hand, they increase air speed.


A new and effective way of guaranteeing good ventilation in the barn is to use overpressure tube ventilation, also called tubes. Here, fans are connected to an air hose and the fresh air is sucked in from outside. The hose system allows even distribution of the air throughout the barn. This happens through small, precisely calculated outlet openings along the hose. “Poor quality” air is forced out of existing openings such as windows and doors by overpressure. Tubes make it possible to regulate airspeed precisely without causing drafts at head height and to transport fresh air to exactly where it is needed. [5] [6]Conventional tubes, as described above, are mainly suitable for ventilation but there are also special solutions that contribute to cooling. Here, the air comes out of the holes much faster. [8]

“Cow showers” – high-pressure and low-pressure systems

There are of course other solutions which enable the farmer to make summer as tolerable as possible for his dairy cows. “Cow showers”, for example, can be installed as high-pressure nebulization and low-pressure spraying systems. Both systems have their advantages, but farmers must be particularly careful with humidity in the barn. Humidity in the barn should not be too high as in addition to temperature, high humidity also promotes heat stress in dairy cows. Therefore, the use of these systems is recommended only in modern stables with high air volume and a high air exchange rate. Furthermore, they are only really useful if operated intermittently in combination with fans. [9]

When using low-pressure systems, water is sprayed onto the cows in large drops, producing evaporative cooling as the fur dries. These systems should be installed where neither cubicles nor food gets wet. In addition, it needs to be taken into consideration that if too much water is sprayed and does not evaporate quickly enough, it runs down the stomach to the cow’s teats. In particular, if animals are very wet and go to the feeding station after milking, germ-contaminated water droplets may form on the teats. Since after milking the so-called Fürstenberg‘s rosette takes a certain time to close the teat canal, germs can enter into the udder very quickly and mastitis can occur.

High pressure systems only deliver finely atomized water. Cows do not get wet, but the water mist only extracts heat from the air. Using such a system, the risk of high humidity is particularly high.

Construction measures

However, it is not only retrospectively acquired technical systems that can improve the climate conditions in the barn. It is also possible during construction of the barn to ensure that a selection of suitable air intake and outlet openings are planned. There should always be enough air intakes, which provide ventilation over a longer period of time, as well as enough air outlets in the barn. They guarantee that humidity levels remain stable. [7]

Another possibility for ensuring efficient ventilation and air conditioning are stable walls, which can be fully opened in summer. “Classic” stable windows are replaced by sliding double-skin sheets. This not only improves air exchange but also increases natural light sources in the barn. In order to prevent punctual drafts, it is recommended that equally large window areas be installed on both long sides of the barn. [7]

How can smaXtec help with air conditioning of the barn?

With the help of the Climate Sensor, smaXtec offers, in addition to the animal-specific monitoring of body temperature and activity, the ability to detect heat stress at a very early stage.

The Climate Sensor is installed in the barn and measures air temperature and relative humidity. From these two parameters, the so-called THI value (Temperature Humidity Index) is calculated. This number provides information about the intensity of the heat stress.

  • THI ≥ 72: early stage of heat stress
  • THI ≥ 78: significant heat load
  • THI ≥ 82: severe heat stress

Based on data collected by the smaXtec Climate Sensor, the system informs you as soon as the temperature and humidity are in a health-threatening range.

This means that the ventilation systems, fans or water spray systems can be used with pinpoint accuracy and in an energy saving way. Air conditioning systems are only used if heat stress occurs in your dairy cows.


For more information about the smaXtec Climate Sensor or to receive a customized quotation, please contact us.










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