Abstract
Holstein cows (20) were used to determine the effect of reducing amount of water use for evaporative cooling (WEC) system on animal productivity. The first group served as control and the other group was maintained under the same condition except that WEC system was timed for 5 min on and next 5 min off. A telemetry system was used to monitor core body temperature (T-corc) at 5 min intervals throughout the experiment. Core body temperature exhibited a circadian rhythm reaching maximum during middle of day and minimum in early morning. The 50% reduction in WEC resulted in a significant increase in daily average T-corc that was not associated with a significant reduction in milk production. In conclusion. the 50% reduction on WEC did not have any adverse effect on animal productivity, therefore we strongly recommend applying a 5 min cycle system.