Long Day Lighting

Research has shown that when cows are exposed to 16- to 18-hour days, they will produce 4 to 5 pounds more milk per day. Long days can be simulated by exposing the cows to artificial or a combination of natural and artificial light. In a tiestall barn this can be accomplished by installing a row of T8 fluorescent fixtures over the feed alley. In a freestall barn, metal halide high pressure sodium, induction or fluorescent (T5 or T8) lamps can be used unless the ceiling height is less than 10 feet, then T8 or T5 fluorescent fixtures are recommended. Using long-day lighting doesn’t reduce energy input, but the increase in milk production reduces the cost of milk per unit of energy used. For more information, refer to the links in the References section.