Recorded live at the American Dairy Science Association (ADSA) 2026 Annual Meeting as part of the Real Science Exchange podcast, this episode explores how the dairy industry can move beyond simply coping with heat stress toward building more resilient cows and systems, from individual cow resilience and immune function to strategies for cows and calves.
The panel features the speakers behind the symposium "Concepts and Strategies to Improve Physiological Resilience to Heat Stress in Dairy Cows": Dr. Yun Jiang (University of Wisconsin-Madison), Dr. Jimena Laporta (University of Wisconsin-Madison), Dr. Vincenzo Lopreiato (University of Messina), and Dr. Maya Zachut (Volcani Institute).
The episode begins with introductions. Dr. Jiang describes her research on stress mitigation and dairy nutrition sustainability, and Dr. Laporta shares her path from the University of Florida to UW. Dr. Lopreiato, based in Sicily, notes he has worked on heat stress for three years. (00:00 – 03:48)
The discussion turns to heat stress as a global issue. Dr. Zachut explains that cows in Israel are now considered heat stressed eight months a year, and that the topic has become relevant even in northern regions. She stresses that even the most advanced cooling systems cannot fully alleviate heat stress, which is why the symposium brings physiology and nutrition together. (03:49 – 09:19)
Dr. Jiang then shares her work on why some cows are naturally more resilient, showing smaller milk drops and less rise in body temperature. Resilient cows produced less methane and had lower inflammation, and she suspects differences in energy metabolism. With 64 cows, she notes the study was too small for genetic analysis. (09:20 – 11:58)
Attention then shifts to the dry cow and the "transition calf." Dr. Laporta explains that heat stress in the first 60 to 90 days of life affects the mammary gland, ovary, thymus, and spleen. Cooling pre-weaned calves improved survival and slightly increased milk production later as cows, an opportunity she calls practical for producers facing replacement shortages. (11:59 – 19:37)
Dr. Zachut next presents a 2x2 study comparing three versus six cooling sessions per day in mid-lactation cows, with or without beta-caryophyllene, a dietary cannabinoid. More cooling improved welfare, behavior, and milk production, but surprisingly had little effect on immune function after an intramammary LPS challenge. The best cooling plus the supplement showed synergistic effects. (19:38 – 26:10)
Dr. Lopreiato then discusses methionine and plant polyphenols, which both activate antioxidant defenses. He notes that even with efficient cooling, milk losses can reach 15%, and he suggests oxidative stress may be a key driver of heat stress damage. (26:11 – 32:18)
Particular emphasis is placed on fine-tuning, not suppressing, the immune response. Dr. Zachut calls cooling by far the strongest tool, but cows cooled three times daily with the supplement had resting times similar to cows cooled six times. The panel also discusses capsaicin-containing extracts, which may increase sweating, while Dr. Lopreiato highlights the importance of rumen protection. (32:19 – 38:47)
The panel also explores immune function in calves. Dr. Laporta explains that heat stress activates the calf's immune system but makes it less effective, with lower neutrophil function and more illness. Dr. Zachut sees young calves as an opportunity to feed polyphenols before the rumen is fully functional. (38:48 – 43:53)
The conversation concludes with key takeaways. Dr. Zachut notes that even the best-cooled farms still see losses in fertility and immune function, while Dr. Jiang asks whether heat-stressed cows have different nutrient requirements. Dr. Laporta emphasizes there is no one solution and that early life matters for building cows resilient to climate change. (43:54 – End)
Throughout the episode, the panel reinforces a central message: cooling remains essential, but it is not enough on its own, and pairing good management with targeted nutrition across every life stage offers the greatest opportunity.
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