How Better Ventilation and Cooling Protect Dairy Cows from Heat Stress

Heat stress is often underestimated in the UK dairy industry. While hot weather events may only last a few days, their impact on cow welfare and productivity can last much longer. Findings from the Animal Centred Controlled Environment for Dairy (ACCED) project highlight just how significant this impact can be – and how effective ventilation and targeted cooling can help protect both cows and milk yields.

The ACCED project (funded by the UK Government’s Innovate Fund), a collaboration between Galebreaker and Smartbell, investigated the effects of heat stress during the September 2023 heatwave on two commercial dairy farms. Using environmental sensors and AI-powered ear tags, the study monitored cow behaviour, feeding activity and milk production to better understand how cows respond to high temperatures and humidity.

The results revealed that heat stress affects cows more quickly and more severely than many producers realise.

Heat Stress: A Hidden Challenge in UK Dairy Systems

When temperatures rise and humidity increases, cows struggle to regulate their body temperature. This combination is measured using the Temperature Humidity Index (THI). When THI levels remain elevated for several days – especially overnight – cows are unable to recover from the daytime heat.

Even in the UK’s relatively mild climate, short heat events can cause long-lasting impacts on welfare and productivity.

The ACCED project showed that the recovery period from heat stress often lasts much longer than the heat event itself, meaning the economic and welfare impacts continue long after temperatures return to normal.

The Role of Ventilation and Targeted Cooling

Effective ventilation plays a critical role in helping cows regulate body temperature. Poorly ventilated buildings can trap humidity and reduce airflow, preventing cows from benefiting from natural cooling.

To address this, the study evaluated Galebreaker’s VentTube Cool, a Positive Pressure Tube Ventilation (PPTV) system designed to deliver targeted, high-speed airflow directly to cows while they are lying in their cubicles.

Unlike traditional fans that only cool a limited area, the VentTube Cool system ensures each cubicle receives its own jet of air, improving convective cooling and helping cows maintain comfortable body temperatures.

What the Research Found

The data collected during the heatwave demonstrated clear differences between cows that had access to targeted cooling and those that did not.

Faster Recovery from Heat Stress

Cows without cooling took 29 days to return to normal lying behaviour after the heat event. In contrast, cows that had access to the VentTube Cool system recovered in just two days.

Lying time is a key indicator of cow welfare and productivity. When cows spend less time lying down, it can negatively affect rumination, milk production and overall health. Faster recovery therefore means cows can return to normal performance much sooner.

Protecting Milk Production

Heat stress also had a significant impact on milk yield. Cows that were not cooled experienced an average loss of 50 litres of milk per cow during the heat event.

In contrast, cows that had access to cooling maintained much more stable milk production, demonstrating the economic benefits of effective heat stress mitigation.

High-Yield Cows Are Most Vulnerable

The study also showed that high-yield cows in peak lactation were the most affected by heat stress. These animals experienced up to a 79% reduction in lying time during the heat event when cooling was not available.

This highlights the importance of prioritising ventilation and cooling for the cows that are producing the most milk, as they are also the animals most susceptible to heat stress.

Precision Monitoring Meets Precision Ventilation

One of the most important outcomes of the ACCED project is the demonstration of how smart monitoring technology and ventilation systems can work together.

Using AI-powered ear tags, changes in cow behaviour such as reduced feeding or altered activity patterns can be detected early. These signals can then be used to trigger ventilation and cooling systems, ensuring cows receive support before heat stress begins to affect productivity.

This approach represents a shift toward precision livestock farming, where environmental conditions are actively managed based on real-time animal data.

Preparing Dairy Farms for Future Heat Events

Climate trends suggest that heat events are likely to become more frequent and more intense in the future. As a result, investing in effective ventilation and cooling systems is becoming increasingly important for dairy producers.

The ACCED project shows that even short periods of hot weather can lead to prolonged impacts on cow welfare, milk yield and farm profitability.

By improving airflow and delivering targeted cooling where it matters most, ventilation solutions like VentTube Cool help safeguard cows against heat stress and support consistent milk production.

Supporting Cow Welfare and Farm Performance

Effective ventilation is about more than comfort – it is about protecting productivity, improving resilience and supporting the long-term sustainability of dairy farms.

The findings from the ACCED project demonstrate that smart ventilation and cooling systems can deliver measurable benefits, helping farmers reduce the impact of heat stress while maintaining high standards of animal welfare.

As technology continues to evolve, integrating environmental control with behavioural monitoring will play an increasingly important role in modern dairy management – ensuring cows remain comfortable, healthy and productive even during challenging weather conditions.