A Cooler Barn Supports Stable Milk Production in Summer

Heat stress can occur at surprisingly low temperatures

Heat stress is often thought to be a problem only during extreme heat waves. However, research and expert assessments show that dairy cows may begin to suffer from heat stress already when barn temperatures rise to around +20 °C, especially when humidity levels are high. In these conditions, cows must use energy to regulate body temperature instead of directing it toward feed intake and milk production.

As outdoor temperatures increase, livestock buildings tend to warm up quickly but cool down slowly. This means that heat stress thresholds are easily exceeded indoors even during short heat spells, and the effects may persist after outdoor temperatures drop again.

For dairy cows, the optimal temperature is below +18 °C. When temperatures rise above +20 °C, cows begin to reduce feed intake and rumination, which quickly leads to lower milk yields, particularly in high-producing cows.

Production losses are quickly reflected in farm economics

The effects of heat stress are not limited to prolonged heat waves. Studies show that even short periods of heat can reduce milk yield by several litres per cow per day. During extended hot periods, production losses of up to 4–5 kg per cow per day have been observed.

In exceptionally warm years, the number of hot days in Finland can rise into the dozens. For example, in 2018 there were around 40 hot days in southern Finland and about 20 in Lapland. In many regions, milk yields remained below normal for up to four months, from May through August.

Targeted cooling is a practical solution for barn conditions

The Rex Nordic HP-19 air conditioning unit offers a practical solution when efficient yet flexible cooling is needed without permanent installation. Designed for professional use, the unit is well-suited for environments where heat load varies throughout the day.

Cooler and drier conditions for the animals

The HP-19 produces cool, dehumidified air and allows it to be directed precisely where it is needed via separate exhaust air ducts. In a barn, this may include milking robot waiting areas, feed table edges, or resting zones where cows spend most of their time.

Research indicates that targeted cooling in animal living areas is more effective than cooling an entire building, as it directly affects feed intake and resting time. By directing cool air to the right locations, effective results can be achieved without cooling the whole structure. This makes the solution energy-efficient and easily scalable for barns of different sizes. If necessary, multiple units can be placed in different parts of the building according to heat load.

Cow behaviour reveals the success of cooling

Based on farm experience and research, the benefits of cooling are quickly reflected in cow behaviour. Heat stress reduces resting time and feed intake, which directly impacts milk production.

When indoor air remains more comfortable even during hot days, cows do not need to spend energy on cooling their bodies. They eat more normally and rest longer, reducing the negative effects of heat stress and helping maintain more consistent production levels.

A cooler indoor environment also encourages cows to return indoors during warm nights, helping to stabilise the milking rhythm and improve overall utilisation of the milking system.

Drier air supports indoor air quality and udder health

High temperatures combined with high humidity place additional strain on animals and degrade indoor air quality. Heat stress has been shown to increase somatic cell counts, which are often associated with compromised udder health. Mastitis can reduce the milk yield of an affected cow by 4–10 percent. According to studies, somatic cell counts are typically highest in late summer.

The HP-19 removes moisture from the air during operation, helping to keep barn air fresher and more comfortable for both animals and staff. Condensed water is collected in the unit’s internal tank, with emptying being the only regular maintenance required.

Better conditions for people as well

Working in barns during hot weather is demanding for people too. Targeted cooling improves comfort in milking areas, feeding zones, and service spaces. As heat load decreases, endurance improves and the working environment becomes safer and more pleasant.

An effective response to summer heat challenges

The Rex Nordic HP-19 provides a fast and practical way to improve barn conditions when temperatures rise. Targeted cooling, humidity control, and portability make it a versatile solution for a wide range of agricultural environments.

When animals feel better, production remains more stable – and working conditions improve at the same time.