Dairy At Glance
Lighting Management in Dairy H

Lighting Management in Dairy House for Increasing Milk Production

Dipanjali Konwar*, Keshab Barman** and Y. Singh***

*Asst. Prof., Division of Livestock Production and Management, F.V.Sc. & A.H., SKUAST-Jammu, R.S.Pura,Jammu; **Asstt. Prof., Animal Nutrition, Cattle Research Station, SKUAST-Kashmir, Safapora, Manasbal, Kashmir-193504, ***Assoc. Prof. & Head, Division of Livestock Production and Management, F.V.Sc. & A.H., SKUAST-Jammu, R.S.Pura, Jammu.


Production performance of dairy caws can be manipulated through various managemental practices. One of such approach is the management of dairy cow's exposure to light or photoperiod. Photoperiod is defined as the duration of light exposure within a 24-hour period. A long-day photoperiod (LDPP) means exposure to 16-18 hours of continuous light followed by 6-8 hours of continuous darkness. A short-day photoperiod (SDPP) is defined as continuous exposure to 8 hours of light followed by a continuous 16-hour period of darkness. In field condition, duration of light less than 12-13 hours of light will yield a short day response. Photoperiod management technique is cost-effective, simple, and does not involve extra labor or cow handling. Use of photoperiod to stimulate milk production in dairy cattle should be considered in all dairy housing (Dahl, et al., 2000, Dahl, 2005).

Benefits of long day photo period (LDPP)

Lactating cows exposed to LDPP with illumination of 15-20 FC show an 8-10 percent increase in milk production regardless of their original production level. The long day photoperiod should begin immediately after calving. Increase in milk production becomes fully apparent 3- 4 weeks later and has a carry-over effect after removal of supplemental light. There is no change in protein or solids content of milk, but slight decreases in fat content, but the increase in milk yield more than compensates for the effect on fat and the cost of the increased feed intake. Cows experience a physiologic stimulus to produce more milk and dry matter intake increases to support the greater milk yield (Peters et al., 1978). In addition, LDPP enhance growth rate, function and hastens puberty in prepubertal calves (Dahl, et al., 2000, Dahl, 2005).

Management of Photoperiod

Lighting Duration

For increasing milk production during lactation, maintenance of 6-8 hours of uninterrupted darkness each day is required. Continuous, 24 hour lighting is not recommended as it provides no additional milk productivity over 16 hours of light. Dairy cows require 6–8 hours of uninterrupted darkness each day to detect and respond to the lengthened photoperiod. It is not necessary to leave a night-light on, as cows are able to find water and feed in the dark.  However, some light may be necessary for management purposes. Low-intensity red lighting (7.5-W bulbs) mounted 6–9 m apart and 3 m above the floor provides adequate lighting for observing cows without upsetting the photoperiod response. Installation of timers to control the lights is recommended, as timers eliminate human error and maintain consistency of the lighting schedule. Timers can also be set to turn lights off once full daylight intensities are attained, thereby reducing electrical costs.

Intensity of Light

The initial step in adoption of photoperiod management is evaluation of the light. Light is measured in foot-candles (FC) or lux (lx), with 1 FC = 10.8 lx. To observe a production response in lactating cows, an intensity of 15 FC at 3 feet from the floor of the stall is recommended. Responses have been observed at intensities as low as 10 FC, but the extra 5 FC gives a buffer for dirty lamps, burned out bulbs, etc. Light intensity can be measured using a light meter. If the measurement of available light shows intensity levels below the desired amount then improvements to the supplemental lighting system should be made (Dahl, et al., 2000, Dahl, 2005).

Type of Lighting

Metal halide (MH) or high-pressure sodium (HPS) lights are two energy-efficient ways to light free stall barns. The choice of lighting type should be made according to efficiency and the mounting height most appropriate to the barn. In tie-stall and stanchion barns the relatively low ceilings allow use of fluorescent lights only (mounting height of 8-10 ft). In free stalls, lights can often be mounted at heights of 12 to 16 ft, thus, metal halide or high pressure sodium lamps are appropriate.

To calculate the number of lights required for a barn, the following formula can be used

Number of fixtures required=

Square footage of barn x 15 FC x K
Lumen output per lamp

  • 15 FC (foot candles) is the minimum intensity required for the light period.
  • The K is a constant that accounts for light reflected in and escaping from the barn. Use K=2 in enclosed barns and K=3 in open-sided free stall barns.

Light levels should be uniform throughout the barn, or at least anywhere the cow can see light. The entire barn should be illuminated to an intensity of 15 foot-candles (FC). Appropriate dispersion can be achieved with correct mounting height and distance. Mounting height is measured from the bottom of the lamp to a level 3 feet from the floor of the stall and a rule of thumb for placement of lamps is a mounting distance that is 1.5 times the mounting height. Placing fixtures at an appropriate height can help achieve uniform distribution.   A common mistake is to place lights only above the feed bunk and not evenly throughout the entire free stall barn. A cow typically is at the feed bunk 3-4 hours per day and resting in a free stall 9-14 hours per day. If the lighting is inadequate in the free stall, where the cow spends most of her time, she will not be exposed to the required photoperiod (Dahl, et al., 2000, Dahl, 2005).

Benefit of short day photoperiod (SDPP)

For increasing milk production in subsequent lactation, the dry and primiparous cows should be exposed to SDPP at least during the last 60 days prior to parturition. Limiting light exposure of the dry cows to less than 12 hours each day allows their internal clock to reset, ensuring that during their next lactation a long-day photoperiod can again affect milk yield. In addition to increasing milk production SDPP during dry period improves the immune function of the dairy cattle (Millar et al., 2000).

Housing Management

Milking and dry cows needed different photoperiod. Milking cows need an LDPP and dry cows need an SDPP, they cannot both be housed in the same barn. Milking cows can continue to be housed in a well-lit, naturally ventilated barn with supplemental lighting, but dry cows will need a barn that can be darkened. Since light levels cannot be reduced in a naturally ventilated barn, dry cows will require separate housing with fan ventilation. Designs using adjustable air inlets or tunnel ventilation can be used for dry cow housing. Given a typical 2.2 kg/d response to LDPP, a 0.9 kg/d increase in DMI should be planned for to support the higher milk yield (House, 2006).

 Photoperiod management offers dairy producers a novel tool to improve the efficiency of milk production. It is cost effective on dairies of all sizes. Treatment to increase day length should be considered during lactation and decrease day length during the dry period to increase milk yield.


Dahl, G. E., Buchanan, B. A. and Tucker, H. A. 2000. Photoperiodic effects on dairy cattle: A review. J. Dairy Sci83:885–893.

Dahl G. E.  2005. Let There be Light: Photoperiod Management of Cows for Production and Health. Proceedings 42nd Florida Dairy Production Conference, Gainesville, May 3, 2005 41

House, H. 2006.  Energy opportunities: Lighting for more milk. http://www.omafra.gov.on.ca/english/engineer/facts/06-053.htm.

Miller, A.R.E., Erdman, R.A., Douglass, L.W., and Dahl, G.E. 2000. Effects of photoperiodic manipulation during the dry period of dairy cows. J Dairy Sci83:962-967.

Peters, R. R., Chapin, L. T., Leining, K. B. and Tucker, H. A.1978. Supplemental lighting stimulates growth and lactation in cattle. Science 199:911-912.

Akshay Sadana


Posted Date : 04/04/2015 Posted By : Admin