Research over the past 33 years has shown that long-day lighting (LDL) has a significant positive impact on milk production in dairy cows. LDL refers to increasing the daily light photoperiod for milk herds to 16 to 18 hours at intensity of 15 to 20 foot-candles of light, followed by a dark period of 8 to 6 hours of three foot-candles or less of light. However, Michigan dairy farmers have been unsuccessful in attaining the full benefits of LDL due to technical difficulties in measuring/maintaining light intensity and appropriately controlling the lighting system.
Wing Acres Dairy LED long-day lighting project
In cooperation with the Michigan Milk Producers Association (MMPA), a long-day lighting project, funded by a grant from the Michigan Energy Office, was initiated by Biosystems and Agricultural Engineering Department researchers at Michigan State University to address the technical difficulties referenced earlier. Using light emitting diode (LED) lights, automated sensors, and an automated control system, a LDL system was created at Wing Acres Dairy that successfully resolved the technical difficulties encountered by Michigan dairies. The LDL system has been fully operational since January 2014.
Wing Acres Dairy is a 100 cow dairy in BarryCounty. Over the past 12 months the dairy experienced an 8 percent increase in milk production. Two factors, farm operational practices and weather conditions, were examined to determine if the increased milk production could be attributed to LDL or something else. An examination of farm operation data from 2012 and 2013 indicated that feed quality, herd size, and animal husbandry practices did not change significantly. In 2014 no changes in management practices were made that affected the milking herd. The impact on milk production of last year"s favorable summer temperatures (i.e. cooler temperatures) was more than countered by the terribly cold winter. Based on MMPA data, member dairies had an average drop in milk production of over 9 percent during the February-to-March 2014 time period, more than negating any potential increase in milk production gained during the cool summer. A look at the 2012-2014 historical milk production records of Wing Acres Dairy showed that the so called "summer production dip" was absent, which is indicative of a well-ventilated cow barn, thus limiting the expected cool summer benefit since the cows were never stressed that much in the first place. One can reasonably conclude then, that the increased milk production at Wing Acres Dairy can be attributed to the LDL system.
Implications of the LED long-day lighting project
By replacing metal halide lights in the barn with LED lights, the owners anticipate at least a 50 percent reduction in lighting expenses. Based solely on increased milk production and with exceptional milk prices for 2014, a payback of just over one year is likely for the whole project. This project demonstrates that the technical difficulty of maintaining consistent light intensity and controlling the lighting system can work under Michigan conditions for small, average dairy operations. An accurate and reliable automated control system is the key to successful long-day lighting management. The calibration/modifications of sensors, monitors, programming and making the various components work together to make adjustments automatically in real time was the toughest challenge of this project. Anecdotally, the dairy farmer has noticed that cows in his milking herd have become more docile and less agitated.
LED lighting provides tremendous advantages over other artificial lights due to its low operating temperatures (82 to 113 degrees Fahrenheit), quick starting time (0 to 1 seconds), good color rendering (DesignLights Consortium required 60 plus color rendering index), long lifespan (over 50,000 hours), white color temperature (4,000 degrees Kalvin and above), lack of mercury in the bulbs, and little lamp lumen depreciation (90 percent and above). LED lights have the benefits of low maintenance, better directionality, high lumen per watt ratings, and good color rendering index (CRI). Additionally LEDs can be dimmed, eliminating the need for additional lights for use during the dark period. LEDs are the only truly dimmable lighting systems in the sense that a corresponding decrease in energy use occurs when the lights are dimmed. Other lighting systems can be dimmed but they still use the same amount of energy even though the light output is reduced. Additional saving in labor and maintenance can be attained due to the longer operational lifespan of LEDs.
Payback for LED lighting appropriate for farm use (dust, dirt, and water proof; physical impact resistance; and capable of extreme temperature operation) based solely on energy efficiency does not yet give a desirable investment payback under normal use due to the higher cost of these upgraded LEDs. However, energy savings combined with increased milk production through a well-managed LDL system makes the purchase of farm use LED lighting and the required control/sensor systems affordable.
Funding to implement a LED lighting system
Utility company rebates and USDA REAP and EQIP programs list LED lighting as an approved energy conservation practice. Michigan State University Extension recommends completing a Type 2 ASABE/ANSI S612 energy audit as the first step in securing funding to implement LED lighting. Information on energy audits and funding opportunities can be obtained at energy conservation meetings held throughout the state in January.
Questions concerning the Wing Acres Dairy LED long-day lighting system project, LED lighting and energy audits can be directed to Al Go at email@example.com or 517-214-6128. Questions concerning the energy conservation program and energy audits can be directed to Charles Gould at firstname.lastname@example.org or 616-994-4547.
This article was published by Michigan State University Extension. For more information, visithttp://www.msue.msu.edu. To have a digest of information delivered straight to your email inbox, visithttp://bit.ly/MSUENews. To contact an expert in your area, visit http://expert.msue.msu.edu, or call 888-MSUE4MI (888-678-3464).