The influence of light on dairy cow productivity

Proper lighting in the barn ensures optimal cow productivity, i.e. milk yield. It has been proven that proper illumination in the barn (100-200 lux are needed) can result in a 6 to 10 % increase in milk production.
(source: http://www.lely.com/en/housing/lighting-system_2/light-for-cows)

Summary of the results of diverse studies on the effect of lighting intensity on the productivity of dairy cows:

1. A long day photoperiod (16 hours/day) results in increased milk yield, especially when no short day photoperiod is feasible in the dry phase.
2. Heifers should be exposed to a long day photoperiod (16 hours /day) from weaning to puberty, because that supports the development of mammary parenchyma.
3. During the last 60 days of pregnancy, heifers and dry cows should be exposed to a short day photoperiod (8 hours/day), because that maximizes milk production in the subsequent lactation and strengthens the immune system during the transition.
4. According to bibliographical references, the effect of a long day photoperiod starts after 3 to 4 weeks on the average.

Overview of 10 studies on the effect of the photo period on milk yield:

Obvious positive influence of the long day photoperiod on milk yield!

Source: G. E. Dahl and D. Petitclerc, 2003: Management of photoperiod in the dairy herd for improved production and health. J Anim Sci. 81:11-17

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