When cows are exposed to long days, 16 to 18 hours, research has shown they will give 4 to 5 pounds more milk per day. Long days can be created by exposing the cows to artificial or a combination of natural and artificial light.
Long-day lighting worth considering
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Hoffman Farms is a 300-plus-head dairy with 800 acres just west of Chatfield, Minnesota. Hoffman Farms saved energy and money on dairy technology through People’s Energy Cooperative energy-savings rebates. By placing a variable-frequency drive on a 15-horsepower milk pump, the dairy is saving 25,590 kilowatt hours during a 4,000-hour annual run time and $450 in energy rebates. Switching their dairy-parlor lights to light-emitting diodes resulted in excellent savings as well. Changing 26 two-lamp fixtures from T-8 fluorescent bulbs to linear light-emitting-diode bulbs saved 3,333 kilowatt hours and $312 in energy rebates, and another 42 T-8 fluorescent bulbs in different fixtures to linear light-emitting diodes saved 1,116 kilowatt hours and resulted in $168 in energy rebates.
Most dairy barns are too dark. Improving barn lights and operating them according to a specific schedule can improve both the profitability and working conditions on a dairy farm.
Studies show that exposing cows to supplemental light during the short days of fall and winter can increase milk production by about 5 percent to 16 percent.Â
Figure 2. Summary of nine studies reports the effect of long-day photoperiod on milk yield in lactating cows.