It's Not Just About More Fans: More Fans or More Water Alone Won’t Keep Cows Cool.

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You wouldn’t mix a ration with only one ingredient. You balance protein, fiber, and energy to get the performance you want. Cooling cows works the same way. Airspeed, evaporative cooling, and THI-based control have to work together—otherwise, you’re wasting money and stressing cows.

1. THI-Based Control: Knowing When to Cool Most barns have fans turn on when ambient temperatures reach 22–24 °C (72–75 °F). But heat stress begins around THI 68, and that can happen earlier than you think—especially if humidity is high. Waiting means you’re in abatement mode, trying to bring core body temperature (CBT) down after cows are already stressed.

Core Cool uses THI-based automation, not simple thermostats, so cooling starts at the right time and continues as long as conditions demand—including night hours when humidity can keep THI high even as temperatures drop. Why? Because cows are ruminating, heat-generating machines. Not only is ambient air contributing to how hot they feel, but humidity is amplifying it, and their internal heat production is adding fuel to the fire, increasing CBT long before we humans feel hot.

The bottom line is that without THI-based control, your fans and misters may be off at the very moment your cows need cooling to start.

2. High-Speed Air at Cow Level:

Moving Heat Away. Air is the vehicle that removes heat and moisture from the cow’s skin. Fans must bring fresh, dry air into the barn, move it quickly through the cow’s space, and push heat and humidity out.

Without enough airspeed:

• Water droplets sit on the cows or the bedding
• Humidity builds • Cows stay hot and bedding gets wet
• Minimum target: 7.2 km/h (400 ft/min) of consistent airflow at cow level in every stall.

Research-backed: Every 0.44 m/s of added airspeed can reduce THI by about 1.1 points at the cow’s microclimate. Practical result: Cows lie down longer, chew more cud, and shed heat faster.

The Bottom line is: Fans alone aren’t enough—placement and velocity at cow height determine whether cooling actually works.

3. Evaporative Cooling: Pulling Heat Out of the Cow Evaporative cooling is the sweat system cows don’t have. When fine droplets hit the cow’s skin, a combination of airspeed and body heat causes evaporation, pulling heat out.

But it only works if: 

• Droplets are the right size (not mist hanging in the air or soakers flooding the floor) 
• Short cycles are followed by longer drying periods (30–45 s of water, 3–5 min of airflow) 
• Airspeed is present to carry away the moisture and heat 
• Relative humidity is taken into account

Bottom line: 

• Evaporative cooling without airspeed = wet cows and wet bedding 
• Airspeed without water = limited heat removal 
• Adding water without considering THI = wet everything 

You need all components working together.

4. Heat Load: The Hidden Behavior Shift 
Even when bunk-line soaking is running, cows lying in warm beds are still generating heat from rumination and fermentation. If beds are too warm, cows instinctively get up and head to the feed bunk where the soakers run. They look like they’re eating—but they’re not. Their instincts tell them to stop eating to stand and increase their surface area to the airspeed in an attempt to cool off. 
That means: 

• Less true lying time 
• Disrupted digestion 
• More stress on hooves and joints 
• False signals of increased intake when it’s really heat-seeking behavior

Bottom line: Cooling in the beds prevents the buildup of heat load and stops cows from “standing to cool.” Each extra hour of lying time can add about 1.7 L of milk per cow per day—and fewer leg/hoof issues in the fall.

5. The Formula Multiplied Air + Evaporation + THI-based control isn’t additive—it’s multiplicative. 
When all three work together: 

• CBT stays lower and drops faster 
• Lying time rises 
• Rumination recovers 
• Milk yield and fertility rebound 
• Water and energy use become more efficient

When one part is missing, you’re leaving money and performance on the table.

6. Core Cool Systems = The Formula in Action 
Core Cool isn’t “more fans” or “more water.” It’s a system designed around the cow: 

• THI-driven automation that runs when cows need it—day or night 
• High-speed airflow at cow level (≥7.2 km/h) in every stall and at the bunk 
• Intelligent evaporative cooling with quad tips that deliver ultra-fine droplets precisely where cows stand or lie 
• At the holding pen where CBT can spike fastest

Bottom line: Cooling the cow, not the barn, in all the places she spends time.

7. Real-On-Farm Proof
One of our customers uses rumen boluses that measure core body temperature every fifteen minutes.
Before installing Core Cool, the biggest spikes in CBT happened between midnight and five a.m.

Why? It is most likely because the cows were waiting until nighttime to eat when it was cooler. Then, during rumination, the heat from fermentation pushed their body temperature up.

Since humidity is often highest at night, even though the air temperature drops, the THI stays elevated—making it tough for cows to shed that heat.

After Core Cool was installed, those nighttime spikes disappeared. The cows ate whenever they wanted—day or night—and their core temperatures stayed steady. On-Farm proof that investing in a system that adjust to meet the temperature and the humidity can have a significant impact on cow comfort and performance. 

8. Let's get down to the dollars and Sense

Let’s face it — the dollars we spend on a system have to make good financial sense.”
Heat stress costs producers money, time, and performance — and surprisingly, most of those losses come from mild, prolonged stress that often goes unnoticed.

You can’t fix that with more fans or more soaking. You fix it with a smarter system that prevents heat stress before it happens.
Because prevention is always cheaper than abatement — reacting after the cow is already heat-stressed.

Here's a few Final Takeaways

Cooling your cows is just like balancing a ration — all the components have to work together, providing exactly what the cows need to deliver the results we’re working for.
With Core Cool, you get the full formula in motion: THI triggers, high-speed air, and intelligent evaporative cooling — working together day and night.
Your cows are your biggest investment. Without that milk check, there’s no need for the robots, the TMR mixer, or the kernel processor on the combine.

Keeping cows cool, comfortable, and performing at their best isn’t a luxury — it’s good business.
It makes good business sense to keep your biggest revenue-generating asset cool, comfortable, and performing at their best—that means more milk in the tank and more money in the bank.

Let’s chat about what’s happening on your farm, how things are working now, and what could use some improvement. Our team will work with you to build a tailor-made solution. 📞 Call +1-330-717-8852 or email nancy@corecoolsystems.com to connect with your local Core Cool agent.