A-SHED research reveals how dairy farmers perceive heat stress and why it can be easy to miss

In colder regions of the UK, heat stress may not be at the forefront of farmer’s minds.

In Northern England and Scotland, a stronger focus is often on keeping livestock warm and comfortable in harsh winter conditions.

Despite the warming climate, Galebreaker’s new research from a two-year collaboration between Scotland’s Rural College (SRUC) and industry partner, Smartbell, has shown a disconnect between farmers experiencing heat stress first hand while not considering it a local problem.

In this blog, animal welfare specialist Chloe Rodriguez shares the project’s farmer survey findings and talks us through how the A-SHED project is using data to improve cow welfare and performance.

What farmers told the A-SHED project

The A-SHED farmer survey had 38 respondents, 20 responses from Scotland, 15 from England and the remainder from Northern Ireland and Ireland. The herd size ranged from 50 – 400 cows, mostly above 100-head herd.

While 84% of respondents believed their herd had experienced heat stress, only 74% perceived it as an issue in their region. Chloe says the A-SHED project aims to bridge this gap.

“It’s encouraging that many dairy farmers recognise that heat stress affects their cows,” she says.

“However, a significant proportion still don’t consider their region to be at risk, meaning heat stress may be occurring more frequently than they realise.”

Why heat stress can be difficult to recognise

Chloe says the survey highlighted where the perception gap appears to come from and says there are three main areas.

1. Understanding of temperature and humidity

 “Farmers gave a very wide range of answers about when cows begin to experience heat stress. The estimates reported ranged from 10 – 30°C,” she says.

“We also found uncertainty about how humidity affects the cow. Monitoring temperature alone can be misleading, as humidity is a big driver of heat stress.”

She says understanding this interaction means farmers are better able to manage heat stress effectively.

“Assessing housing conditions purely based on temperature alone or basing it on your own physical comfort is where the disconnect can happen, as cows cope differently to humans,” she adds.

“The best measure of environmental conditions is THI as it combines air temperature and humidity, to give a single value index.”

An example highlighted by one dairy unit in the A-SHED project logged a 97% humidity reading while having an internal temperature of just 19°C.

“Combining these figures into a single measure of thermal stress gives a THI of 67– enough to create conditions that can start negatively affecting cows’ welfare and metabolism,” she says.

2. Low use of active monitoring

Although many farmers value operational data, only 18% of respondents reported measuring shed temperature.

“When we collect farm specific environmental data, it allows us to accurately advise on how best to improve the housing,” Chloe explains.

“As part of the A-SHED project, we’ve installed THI loggers which are linked up to THI-Live.com.They can be used to actively alert farmers when THI thresholds are exceeded.”

Almost two-thirds of participants expressed interest in having tools that give farm specific daily guidance. Satisfying this appetite for practical, system-specific advice is something the A-SHED project is working towards.

“Every farm building has a different heat-stress risk, influenced by its design, ventilation, stocking rate and management,” says Chloe.

“THI monitoring means producers can identify shed-specific risks, act earlier and ensure buildings continue to protect herd welfare and performance in the future.”

3. Mitigating the risks of heat stress

From the survey, A-SHED has found variation across farms with how they reduce risks of heat stress.

Chloe says most dairy units implement at least one infrastructure-based solution:

• Open-sided sheds (55%)
• Flexible openings (32%)
• Positive pressure tube ventilation (PPTV) (47%), like Galebreaker’s VentTube Cool.

“Mechanical ventilation systems can have a huge impact on cow comfort, especially when retrofitted to older sheds,” she explains.

Why heat stress matters

Cow welfare

Chloe says temperature, humidity, lack of air movement, inadequate building design, high stocking densities and limited overnight recovery periods can all contribute to:

• Increased respiration rates
• Reduced lying times
• Bunching around water sources
• Lower milk yield
• Less feed intake

“These are signs of heat stress which all directly affect cow welfare and performance,” she says.  

Climate change

With the UK experiencing multiple heatwaves this year, Chloe says THI is becoming an increasingly important measure to farmers.

“Over the past two summers, housed dairy cattle across northern England and Scotland experienced significant heat stress due to periods of prolonged high THI,” she adds.

Even in the typically cooler regions in the UK, Chloe says on average, July 2025 was the hottest month in Scotland and northern England. Mid-August 2025 also saw persistently high THI levels

Bridging the gap

Chloe says the A-SHED project will continue working with farmers to mitigate heat stress.

“From THI data, we can develop advice that fits individual farming systems and help farmers recognise risk earlier,” she adds

“Heat stress is now a challenge that affects all regions of the UK and should be incorporated into herd management, to keep cows comfortable and reduce any losses for the farmer.”

Get in touch

Contact Chloe at crodriguez@galebreaker.com for personalised advice on improving your livestock housing and to book an on-farm advisory assessment.