Toward Energy-Efficient and Welfare-Oriented Lighting Design in Dairy Barns

Abstract

Lighting plays a crucial role in dairy production, impacting milk yield and cow well-being. In Sweden, where cows spend winters indoors, adequate lighting is essential for animal welfare, regulatory compliance, and stable milk production. This study explores how natural and electric lighting can be combined to optimize dairy farm environments and prevent heat stress. The research assesses the effects of lighting on cow behaviour, health, and milk production, while proposing cost-effective lighting solutions. Key objectives include evaluating lighting regulation compliance, measuring daylight performance, and understanding cows’ light perception. Long-term data on lighting, temperature, and cow activity were collected to examine how these factors influence cow activity, health and production. The thermal impact of different lighting strategies was also assessed, comparing solar radiation and electric lighting with heat gains from cows. Findings show that LED lighting reduces energy use, meets both visual and biological needs of cows and workers, while preventing heat stress. Skylights are effective for natural lighting but must be carefully managed to avoid excess heat unless shaded. The colour and reflectance of interior surfaces further optimize overall illumination. While lighting and temperature affected cow behaviour, health, and milk yield, social dynamics and management practices also played a significant role. This research offers practical recommendations to improve energy efficiency and lighting design in dairy barns, supporting sustainable production while enhancing cow comfort and welfare under real-world conditions.

Popular Abstract

Lighting the way to sustainable farming, healthier cows and higher yields
Smart lighting in dairy barns can improve cow welfare, reduce energy use, and increase milk
production.
Switching from traditional metal halide (MH) lamps to light-emitting diode (LED) lighting has
benefits beyond energy savings. LEDs emit more blue and green light, which better aligns with how
cows perceive and respond to light. Cows, like humans, use light to regulate their internal clocks,
which influence sleep, health, and milk yield. The right light at the right time helps them rest better,
stay healthier, and produce more milk.
But good lighting design involves more than just swapping bulbs. Barns need a careful balance of
daylight and electric light. While skylights can brighten spaces naturally, too much
sunlight—especially without proper shading—can overheat barns, causing stress that reduces milk
production. Our research emphasizes the importance of integrating daylight with energy-efficient
LEDs, while considering the combined effects of light and temperature on cows’ well-being and
productivity.
Lighting alone isn’t the full story. Routines, social behaviour, and barn layout all affect comfort and
productivity. Effective lighting design is one important piece of supporting overall animal welfare and
farm efficiency.
To find good lighting solutions, we combined real-world measurements with computer simulations. In
a Swedish barn lit by MH lamps, we tracked light and temperature levels during the spring 2025,
along with cow health, behavior, and milk production. This helped us understand how the animals
responded to seasonal weather changes. At the same time, we used daylighting simulations to test
different retrofit strategies— to improve lighting while avoiding overheating or extra energy use.
The results were clear: lighting isn’t just about seeing. Poor lighting can lead to stress, reduced milk
yields, and unsafe working conditions. When designed thoughtfully, lighting can support natural
rhythms, enhance productivity, and create a safer, more efficient setting for both cows and farmers.
However, more studies are needed to fully understand and confirm the direct effects of lighting on
animal welfare and to develop guidelines that best support the health and comfort of dairy cows.
This need for better lighting design is becoming even more urgent as climate change brings warmer
weather. Barn lighting not only affects comfort and productivity but also plays a crucial role in
temperature regulation and energy efficiency, making smart lighting a key tool for sustainable dairy
farming.
It’s also important to consider species-specific needs. While humans find warm red light comforting,
cows can’t see it at all. A barn lit for human preferences alone might leave the animals in the dark.
Tailoring lighting for both species ensures healthier cows and better working conditions.
Our findings offer practical guidance for farmers, designers, engineers, and policymakers: avoid
oversized skylights in well-lit barns, install shading where needed, and choose high-quality LED
systems with smart controls.
Barns are more than shelters—they’re homes. When we light them well, we support happier, healthier
cows, reduce costs, and promote sustainable farming.
The takeaway? Smart lighting isn’t just about saving energy. It’s about designing for well-being,
productivity, and resilience in the face of climate change.

• author: Andersson, Ellen and Su, Yixin
• supervisor: Marie-Claude Dubois; Sheikh Rishad Ahmmad
• organization: Division of Energy and Building Design
• course: AEBM01 20251
• year: 2025
• type: H2 - Master's Degree (Two Years)
• subject: Technology and Engineering
• keywords: Energy efficiency, dairy cows, animal building, lighting, animal welfare, daylighting
• language: English
• id: 9195030
• date added to LUP: 2025-06-11 08:26:55
• date last changed: 2025-06-11 08:26:55