Good lighting in combination with a good day/night rhythm in the barn is the basis for optimally performing cows.
During farm visits I regularly see barns that are insufficiently lighted, (even during the day).
I have the impression that in practice the influence of light on the optimum performance of calves and cows is often underestimated.
In addition to a day and night rhythm, cows need a certain level of light to be able to make full use of the day and night blocks physically.
This primarily affects milk production.
A well thought out lighting schedule combined with an optimal lighting plan reduces shadow in the cowshed.
It also guarantees sufficient light during the day and a sufficient (dark) period for rest.
With sufficient light on the retina of the eye, the secretion of the hormone melatonin is inhibited.
The pituitary gland plays a controlling role in this. Melatonin induces sleep, increases body fat percentage and disrupts the cow's production capacity.
Once melatonin levels drop, the hormone IGF-I is boosted.
The function of IGF-I is to increase activity in the animal, resulting in higher milk production.
Therefore, the right amount of light and a good day/night rhythm gives higher milk production.
In fall, winter and spring, even with the available lighting, the required light level in cowsheds is often not achieved.
I consider a continuous light period of 16 hours and a light intensity of at least 180 Lux at animal level, followed by a dark period of 8 hours as the optimum.
During the summer period, the natural light level in the barn is normally sufficient.... However, measuring can't do any harm!
Therefore, I am in favor of automatic (on light intensity), controlled barn lighting.
Summer also has many dark and cloudy days.
Such days can have a negative influence on the (milk) production of cows kept in barns.