Have you ever experienced a day so humid that you find yourself dripping in sweat sitting in the shade on the front porch? Those days are brutal. Imagine how those days feel for your cows! They can't sweat the way we do to help regulate their body temperature. We know how damaging high heat and high humidity can be to cattle health and performance.
What is exactly is humidity? Humidity is the amount of water vapour in the air. Too much or too little humidity can be dangerous. For example, when we add high humidity with high temperatures, we get a combination that causes severe heat stress in dairy cattle.
Humidity plays a vital role in our ability to manage heat stress on farms.
When we talk about humidity, there are two different terms: absolute humidity and relative humidity.
Absolute humidity is the amount of water vapour divided by the amount of dry air in a certain volume of air at a particular temperature. The hotter the air is, the more water vapour it can hold.
Relative humidity is the ratio of the current absolute humidity to the highest possible absolute humidity, which will depend upon the current air temperature. Relative humidity is the term weather forecasters use most often.
Relative humidity of 100% means that the air can't hold any more water vapour. It's totally saturated.
So how does humidity affect the evaporative cooling of cows on a hot day?
If the temperature outside is 75° F/23.8° C, humidity can make it feel warmer or cooler. Relative humidity of 0% would make it feel like it's only 69° F/20.5° C. On the other hand, relative humidity of 100% would make it feel like 80° F/26.6° C.
If the humidity is low, evaporative cooling is much easier. The dry air helps the added moisture evaporate and produces a chilling effect on the blood flowing just below the surface of her skin. Like when you're standing on the hay wagon on a hot July day, sweating buckets and a warm breeze blows past, and you suddenly feel pleasantly cooler.
In areas where the relative humidity is high, the air is already saturated with water vapour, so it can't gather as many moisture molecules as it travels past. This is when airspeed AND intelligent water cooling determined by the temperature-humidity index in the barn becomes crucial. The fully saturated air needs to be exhausted often by very high airspeed to combat the humidity. Fresh drier air needs to be pulled into the barn, gather as much moisture from the air as possible and be exhausted out of the barn. There need to be as many fresh air exchanges per hour as possible to continually pull moisture molecules from the air.
Airspeed is the key; 7-9 mph is needed in high humidity environments—enough water to provide evaporative cooling but not enough to soak the cow. Using massive amounts of water to completely soak the cows adds huge amounts of moisture into the already saturated air adding to the humidity AND wastes a very precious resource on a hot day. Water. Trust me. There is nothing worse than 100 thirsty cows banging at an empty water trough on a hot day cause the bunk line soakers drained the well!
Research has proven that low-pressure, low-water volume water cooling can achieve the same cooling results as high-pressure, high volume water cooling, Cooling with low-pressure vs. high-pressure research study while using 43-75% of the water of soaker systems.
The KühlerZ system injects a timed, fined mist intermittently meaning the water system shuts off so soaking the coat doesn’t happen. For example, the water may be on for one minute then off for 3-5 minutes to allow time for it to evaporate and for the airspeed to move the fully saturated air out of the barn. That is how the system is able to cool even when humidity levels are very high. Systems that offer less airspeed can't exhaust the moisture-laden, saturated air fast enough to combat the humidity and provide cooling to the cows.
How about dealing with high humidity in cooler months?
In areas where humidity is high throughout the cooler winter months, a KühlerZ system can greatly impact herd health and productivity. Ever walk into a barn in the winter and have that thick, stagnant air hit you right in the face? Has that heavy air hitting your lungs made you cough? Of course, we have all experienced that. The variable speed capabilities of a KühlerZ system mean that we can program the fans to come on at less than 50° F10 °C. Operating at 30% power, the fans are incredibly efficient and quiet. Cows are continually breathing condensation into the air. Generating moisture that can accumulate in the air. The system comes on, dries up all the condensation, moves the stale air out and brings in fresh dry air.
Stand By Mode is the mode a KühlerZ system is in when the temperature is below 10 °C. A new feature of the Core Cool system is that in standby mode, the fans continue to turn slightly, helping dry the condensation and humidity from the air. The air won't be moving fast enough to cause a chill. It will just gently push the air along and out of the barn. Keeping the air fresh and dry.
So the answer to the question, Can you use evaporative cooling in high humidity? Is Yes, you can with a KühlerZ system.
The versatility of the KühlerZ system creates extreme value for our customers and their cows. When cows are provided with consistency, they can reach and maintain their full potential. KühlerZ offers this consistency. Every day will feel like a cool spring day. Imagine the possibilities.
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