In modern dairy farming, lighting is too often seen as a passive utility. In reality, it's a powerful tool - directly influencing biological performance, animal well-being, and operational outcomes.
At the center of this influence lies the circadian rhythm: the internal clock that governs cows' metabolic, hormonal, and behavioral cycles.
The circadian rhythm is a 24-hour internal timing system regulated by light-sensitive neurons in the brain. In cows, this system governs:
Disrupted light cycles, such as 24-hour lighting or poor spectral quality, can impair feed conversion, fertility, and milk yield.
Dairy research shows that extending photoperiods to 16–18 hours of daylight, followed by 6–8 hours of darkness, can increase milk yield by 3–7%.
This happens through:
However, these gains only materialise when light quality, spectrum, consistency, and biological timing are optimised - not simply when brightness increases.
Designing lighting systems for biological needs
A high-impact lighting system includes several core components:
Photoperiod management: Milking cows benefit from a Long Day Photoperiod (LDPP), which means 16–18 hours of light and 6–8 hours of full darkness.
In contrast, dry cows respond better to a Short Day Photoperiod (SDPP), typically 6–8 hours of light and 16–18 hours of darkness. An effective lighting climate for lactating cows includes an automated regime delivering 16–18 hours of 200 lux per m², followed by a consistent dark phase.
Light spectrum: Specific lighting spectrums, used in combination with correct intensity, uniformity, and scheduling, have been shown to support higher milk yields.
Under the RUDAX concept from HATO, the Lactivus Technology spectrum is tailored for dairy cows - suppressing melatonin and stimulating IGF-1 (Insulin-like Growth Factor 1). This keeps cows active longer, helping to sustain high milk output over extended periods.
Consistency and Predictability: Like humans, cows benefit from a predictable environment. A lighting system that delivers consistency allows cows to anticipate feeding, resting, and activity times - reinforcing biological rhythms that directly support milk production. Routine and predictability are key in balancing stimulation and rest.
Lighting is a biological input with direct improvements in milk volume, feed efficiency, animal comfort, and carbon performance. When aligned with cows’ circadian rhythm, light becomes a productivity lever, not just an expense.
For any forward-looking dairy operation, upgrading to biologically intelligent lighting is one of the lowest-barriers to higher-returns.