The above referenced studies looked at systems where sprinkling was being used both in the freestall barn and holding pen. An approach that can achieve moderate cow cooling and use less water would be to start by installing sprinklers and fans in the holding pen. The holding pen is often the hottest environment on the farm.
Cows will quickly experience heat stress when producing large amounts of body heat and brought into a confined space two or three times per day. Michigan State University Extension does not recommend installing sprinklers in the holding pen without mechanical ventilation which can cause more severe heat stress than no cooling because of a rapid increase in humidity.
The amount of water used in holding pen cooling has not been well documented. Harner recommends that sprinkler systems be capable of providing 0.03 gallons of water per minute per square foot of area.
Thermostat settings in the holding pen are recommended to be at 1 minute on, 6 minutes off, which is shorter than in the freestall area. Harner cautions that many water distribution systems may not be able to handle the high flow rate demands of the sprinkler system in addition to normal parlor water use.
Using water and fans in combination to cool cows is an effective way to cool cows during summer months. This approach uses large amounts of water which must be planned for in well capacity and storage.
Using recycled plate cooler water to cool cows can be an effective way of reducing the water demands on the farm.