Heat Stress Slashes Dairy Milk Yields Worldwide

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.