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Heat Stress Slashes Dairy Milk Yields Worldwide

Jul 07, 2025
By Farms.com

Study Links Climate Heat to Long Lasting Milk Production Losses

A major new study confirms that climate change is hurting dairy production globally. Using data from over 130,000 cows in Israel, researchers found that humid heat causes up to a 10% daily drop in milk yields. The effects last over 10 days, even after temperatures cool.

The study focused on wet-bulb temperature, a measure that combines heat and humidity. It found that cows experience high stress when temperatures exceed 26°C, disrupting vital biological functions and milk output.

Even with advanced cooling systems in place, farms only recover half the milk lost at 20°C. At higher levels, cooling becomes less effective.

The study warns that nations like Brazil, Pakistan, and India could lose 4% in average milk yield per cow by 2050 without action.

Farmers benefit from cooling systems, which typically pay off in under two years. However, poorer farms may struggle to afford them, creating inequality in food production.

The researchers emphasize that beyond physical cooling, improving cow welfare is key. Reducing stress from confinement and calf separation helps cows withstand heat better.

As co-author Ram Fishman noted, “the severe impacts observed [in Israel] might be even more pronounced in less equipped regions.”

This research is one of the first to link real-time weather data with milk losses, offering a clearer picture of climate change’s effects on animals.

The study urges global investment in climate-smart agriculture, including breeding for heat tolerance and better policy support. Without action, the future of dairy farming—and a cold glass of milk—could be at risk.


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In this episode of The Swine it Podcast Show Canada, Dr. Claire Mtezankuni, Swine Veterinarian at Carthage Veterinary Service, discusses the growing severity of PRRS outbreaks in sow farms. She explains how respiratory disease and sow mortality are changing outbreak response, why necropsies and bacterial cultures can guide treatment, and how vaccination, biosecurity, pain management, and clear team communication support recovery and elimination. Listen now on all major platforms!

“Emerging PRRS strains can produce severe reproductive and respiratory disease simultaneously, creating substantial health challenges across sow farms during acute outbreaks.”

Meet the guest: Dr. Claire Mtezankuni / claire-mtezankuni-2529b1b3 is a Swine Veterinarian at Carthage Veterinary Service in Illinois, where her work includes commercial farm veterinary leadership, herd health, disease elimination, and veterinary internship coordination. She holds a DVM from the University of Wisconsin–Madison and a Master of Veterinary Science in Livestock Systems Health from the University of Illinois Urbana-Champaign. Learn more from Dr. Claire Mtezankuni on The Swine it Podcast Show Canada, available on all major platforms.