How Mild Heat Stress Eats Into Profits Every Day

You Won’t See It Coming—But You’ll Feel It in Your Bottom Line

Heat stress isn’t always obvious. It doesn’t wait for a 100-degree scorcher to start causing problems. In most dairies, the damage begins quietly—on a humid 75°F day in spring or early summer when cows stop lying down, reduce feed intake, and start losing feed efficiency.
The result? Lost production, fertility problems, rising health costs, and lower profitability. All without a single “extreme heat event.”
If your current cooling system relies on fans kicking on at 24°C/ 76°F, you’re reacting too late. And every hour of delay costs your operation money.

Mild Heat Stress: Real, Measurable, and Daily
Modern dairy cows are not the same as they were 20 years ago. They produce more milk and generate more internal heat. But many barns still operate with outdated cooling systems designed for lower-output cows.

Here's the hard data:

• Heat stress starts at a THI of 68—that’s about 72°F with 45% humidity. Not exactly scorching.
• Milk losses begin immediately—but fertility, immune response, and milk components start dropping even earlier.
• Most barns don’t even activate cooling until THI hits 72–75. That’s not early intervention—it’s damage control.

“Recent research has shown that milking dairy cows start to decrease milk production when the temperature-humidity index (THI) exceeds 68 (i.e., temperature of 72°F with 45% relative humidity, or 80°F with no humidity) and not 72 as shown in previous research with lower-producing dairy cows. The detrimental effects on the estrus expression, conception rates, and early embryo survivability occur before declines in milk production are observed and may occur at a temperature-humidity index as low as 55 to 60.”
Quote Source: https://afs.ca.uky.edu/content/dairy-feeding-and-management-considerations-during-heat-stress

The Hidden Costs Add Up Fast
Heat stress doesn’t just lower milk yield. It chips away at everything that makes your herd profitable:
Lower conception rates mean increased days open
Higher incidence of mastitis, lameness, and metabolic issues
Reduced butterfat and protein levels
More standing time, less lying and ruminating
Elevated core body temperatures for hours—or days—after heat exposure
And these are cumulative effects. One mild heat day won’t crash your herd—but 10 in a row will, quietly and consistently, result in a very big negative impact.

Why Most Cooling Systems Fall Short
Ask yourself: Does your current system focus on cooling the core body temperature (CBT) of cows? Or is it just blowing hot air around?
The typical setup—some fans, maybe a timer-based mister—has major flaws:

• It’s reactive—only kicking on after stress has begun
• It’s based on air temperature, not THI
• It cools the barn, not the cow
• It ignores high-stress zones like stalls, beds, and holding pens

Most importantly, it fails to address the root cause of the problem: the rising incidence of CBT in high-producing cows.

The Danger Zones: Bunks, Beds, and the Holding Pen

Cooling just the air in the barn is not enough. Consider this:

• Cows spend 10–13 hours lying down
• They visit the feed bunk 10–14 times a day, and
• Spend up to 3 hours daily in the holding pen—which is often the hottest spot on the farm.

Without cooling, a cow’s CBT can rise by 3°F in 20 minutes in the holding pen.
With proper airflow and water, it can drop 3.5°F in that same time.
Without proper cooling, a cow’s CBT can rise 3°F in just 20 minutes in the holding pen. It takes hours to reverse that spike, even with cooling elsewhere in the barn. This undoes the benefits of premium feed, elite genetics, and top health protocols. By contrast, effective cooling with fans and soakers can drop CBT by 3.5°F in the same 20 minutes. (Source: Alltech, https://www.alltech.com/blog/beat-heat-stress-these-cool-tips)

If you’re not aggressively cooling the feed bunk and holding area, your best cows are overheating three times a day, every day.

Core Cool Systems: Cooling That Works Where It Counts

Core Cool Systems was designed from the ground up with one goal: keep CBT in the comfort zone—no matter the weather. Our systems are:

• THI-driven: Cooling activates based on real-time stress, not the clock or outside air temperature
• Targeted: Focused cooling at feed bunks, stalls, and holding pens
• Effective: 7km/h or 5+ mph airflow for evaporation, plus fine-mist water that keeps cows cool without soaking bedding
• Automated: No flipping switches, no labor-intensive schedules—just consistent cooling, 24/7

You don’t need a bigger fan, and you certainly don’t need a fan every 20 feet/6 meters. You need a more innovative, better-designed system.

Today’s Cows Demand Better Cooling

You’ve invested in genetics, feed, herd health, and facilities. Don’t let an outdated cooling system be the bottleneck.
Today’s high-output cows produce more heat and face tighter margins than ever. If your cooling isn’t managing CBT you're losing performance you can’t afford to give up.

Stop Chasing Symptoms. Fix the Root Cause.

If you’re waiting until cows are panting to act, you’re too late. If you think your current fans are “good enough,” you’re leaving money on the table.
The real enemy isn’t the heat—it’s inaction.
 

“We aren’t making wet floors; we aren’t making wet feed.  You can put fans and water over stalls; you can also put them over feed bunks. You can really get a full bang for your buck by having water everywhere. This little 25” fan will blow up to 70’. It’s a simple controller; you don’t have to worry about labor, and you don’t have to manually flip the fans on and off. It’s automated, it runs, and you can walk away from it. If you can put a system in that controls itself, that, for the most part, is maintenance-free, that’s always a good system.” CowKühlerZ Series, Core Cool Systems Customer

Core Cool Systems gives you full control over heat stress, CBT, and the health and productivity of your herd. Stop treating the symptoms. Start managing the cause.

Every degree of core body heat matters—and every delay in cooling costs more than you think.
If your system doesn’t respond until THI hits 72, you're already in recovery mode. Let’s work together to build a proactive cooling strategy that keeps your cows comfortable at the feed bunk, in their beds, and in the holding pen.
Talk to Core Cool Systems today—because cooling the cow is what counts. WhatsApp +1-330-717-8852 or email nancy@corecoolsystems.com