Evaporative Cooling For Dairies: Increasing Profits & Keeping Cows Happy

Thursday, July 10, 2014

Cows under heat stress produce much less milk or no milk at all. Using sprinklers in holding pens is an effective strategy for lowering cows’ body temperatures by helping them cool down through evaporative cooling.

Have you noticed your cows eating less, panting more, or standing for long periods of time? As you may already know, your dairy cows are exhibiting signs of heat stress – one of the main factors responsible for the summer drop in milk production and a contributing cause of low fertility.

As ambient temperatures rise over 70° F, cows naturally attempt to cool down through panting and sweating. Dairy farmers in hot environments can take advantage of their cows’ natural cooling methods and speed up the process by installing sprinklers and fans in holding pens, a process known as evaporative cooling.


System Installation

Sprinklers are generally installed approximately 9 feet above the floor of the holding pen on drop hoses. The drops are connected to PVC pipes running from the water supply. The size of the pipe is adjusted for cattle count and desired pressure. The sprinklers are installed in a single row between fan rows, or two rows if the pen is very wide. 

Pressure regulators can be added to the system for better control and optimum performance. 

Goosenecks can also be added to make the installation easier. Once the system is in place, little maintenance is required. The only component needing periodic maintenance is a filter – which is optional if the water supply is pumping relatively clean water.


How Does it Work?

With the system in place, sprinklers are then cycled on for approximately 1 minute, depending on the nozzle water delivery rate, and then off. The length of the cycle time depends on the temperature and humidity in the pen, with more humid environments needing frequent wetting cycles. Generally, sprinklers will wet the backs of cows and then stop to allow the water to evaporate before another cycle begins. With both fans and sprinklers, cows’ body temperatures can begin to drop in as little as 30 minutes.

Due to the short on cycle, it is important to select a sprinkler with a 360° instantaneous distribution pattern to ensure the entire wetting diameter is covered. Equally important is controlling pressure from the pipeline. Sprinklers will need to produce a large droplet size that can penetrate the fur of the cow and reach the skin for optimum cooling.

To ensure droplets are large enough to reach the skin, sprinklers must operate between low pressures of 10 to 20 psi. Higher operating pressures will produce finer droplets which will not reach the skin of the cow and could cause humidity levels in the pen to rise, thereby increasing heat stress.



If you are considering evaporative cooling, please visit any of the sources provided below to help you determine if this heat stress management technique is right for your dairy farm.

Mechanics of Heat Abatement

Cooling Strategies During Heat Stress

Coping With Summer Weather Dairy Management Strategies to Control Heat Stress

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