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

Sammanfattning

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.