COMPARISON OF VARIOUS FAN, SPRINKLER, AND MISTER SYSTEMS IN REDUCING HEAT STRESS IN DAIRY COWS

Abstract

Heat stress in dairy cows causes large losses of milk production, but such declines can be lessened if the cowsare cooled. Two two-year experiments were conducted during four summers to evaluate the effectiveness of various fan,sprinkler and mister systems on cow performance and their environment. Cow housing, if provided, was in an open-sided,well-vented free-stall facility. In experiment 1, cows were either outside much of the time, inside with fans only or insidewith fans and intermittently sprinkled with water. The afternoon air temperature was lower in the sprinkled area and thecows on the sprinkled treatment had greater dry matter intake and milk production during one summer than for cows onthe other treatments. Cows allowed outside produced as well or better than cows left inside with fans only. Inexperiment 2, cows were assigned to treatments in which control cows had limited time inside with fans while other cowswere inside with fans only, fans plus intermittent sprinklers, or fans plus misters. Inside areas with sprinklers or misterswere cooler than with fans only. Cows assigned to areas with sprinklers or misters had lower respiration rates andconsumed more dry matter than cows inside with fans only or allowed access to the outside. Cows sprinkled gave moremilk during the first summer than those on other treatments, but mist in the fan plus mister area was caught in up-draftsand did not reach the cows. Milk production did not differ during the second summer for cows on sprinkler or mistertreatments when the misters were lowered to prevent mist up-drafts. About 10 times more water was used for the sprinklerthan the mister treatments during each of the two years. Proper use of water to cool cows in hot weather reduced milkproduction loss.