As climate change ramps up temperatures around the world, it’s not just humans feeling the heat — dairy cows are struggling, too.
A new study, published in Science Advances, suggests that extreme heat can cut milk production by up to 10 percent, even on farms using advanced cooling systems. In one of the most detailed assessments of how high heat affects dairy cows, scientists analyzed data from more than 130,000 cows over 12 years, tracking local weather patterns alongside milk output.
What they found was striking: when wet-bulb temperatures (a combination of heat and humidity) exceeded 78 degrees Fahrenheit, milk production dropped significantly and took over 10 days to recover.
“Climate change will have wide-ranging impacts on what we eat and drink, including that cold glass of milk,” said co-author Eyal Frank, assistant professor at the Harris School of Public Policy, in a press release. “Our study found that extreme heat leads to significant and lasting impacts on milk supply, and even the most high-tech, well-resourced farms are deploying adaptation strategies that may be an insufficient match to climate change.”
Read More: Farmers Are Breeding Heat-Resistant Cows
Cooling Systems and Climate Change
(Image Credit: Vinai Suwanidcharoen/Shutterstock)
Along with looking at cows, the researchers also surveyed over 30 dairy farmers to assess how well cooling technologies, like fans, water misters, and shaded shelters, are working. Nearly all farms had adopted at least some of these strategies. However, even with these measures, the team found that only about half of the heat-related losses were recovered, and as temperatures climbed, the effectiveness of these cooling systems declined.
“Dairy farmers are well aware of the negative impacts that heat stress has on their herds, and they use multiple forms of adaptation. Adaptation is costly, and farmers need to carefully balance the benefits they obtain versus the costs. This is why we see some investment in cooling measures, but not a complete insulation of cows from their environment, which would be far too costly to implement,” said co-author Ayal Kimhi, associate professor at the Hebrew University of Jerusalem, in the press release.
The implications of climate change extend far beyond the barn. The researchers used their data to project global milk losses by 2050, factoring in both climate projections and current adaptation levels. Without any cooling systems, the top 10 milk-producing countries could see a 4 percent drop in daily milk yields. Even with cooling measures, major producers like the U.S. and China could still lose 1.2 to 2.7 percent per cow per day.
Rethinking Farm Adaptation Strategies
The study’s authors stress that cooling systems alone won’t be enough to protect the global milk supply in an ever-warming world. Broader strategies that consider cow welfare, housing conditions, and even social stressors are essential.
“Our research underscores the value and the limitations of cooling technologies and other efforts taken by dairy farmers to adapt to climate change. Policymakers should look into more strategies to not only cool cows but reduce stressors, like confinement and calf separation. Stressors make cows more sensitive to heat and less resilient,” said lead author Claire Palandri, a postdoctoral scholar at the Harris School of Public Policy, in the press release.
As the climate crisis intensifies, protecting milk production will require more than misting fans. It will demand a rethink of how we care for livestock in hotter, harsher environments before the next heat wave hits.
Read More: Dairy Farm Captures and Cleans Over 80 Percent of Methane Emissions
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As the marketing coordinator at Discover Magazine, Stephanie Edwards interacts with readers across Discover’s social media channels and writes digital content. Offline, she is a contract lecturer in English & Cultural Studies at Lakehead University, teaching courses on everything from professional communication to Taylor Swift, and received her graduate degrees in the same department from McMaster University. You can find more of her science writing in Lab Manager and her short fiction in anthologies and literary magazine across the horror genre.
