Beat the Heat in Three Steps

Profile Picture of Post's Author Wyatt Smith | Posted June 2, 2025

With elevated temps in the forecast, it is an appropriate time to discuss different nutritional strategies for managing summer heat stress. As temperatures rise, cows will show they feel the heat – intakes decrease, meal patterns change, and metabolism and energy requirements are significantly altered. In order to help combat this, there are nutritional strategies we can consider to help offset heat stress and help maintain productivity.

Energy Density and Dry Matter Intake

One of the most critical changes in heat-stressed cows is a reduction in dry matter intake. To compensate for this, we can formulate diets to increase overall energy density to offset the intake loss. The target is to maintain the number of calories consumed each day, despite the reduction in intake. This can be achieved through feeding more digestible fiber, bypass fats, and/or starch sources.

Additionally, under heat stress, cows will reduce their overall number of meals and increase their meal size. This increases the risk for unfavorable rumen conditions which can discourage us from using starch to drive energy density. Considering this, digestible fiber via high quality forages or non-forage fiber sources is the preferred route for maintaining favorable rumen conditions while driving energy density during heat stress. In addition to increasing carbohydrate sources, providing more rumen-undegradable protein (RUP) sources can help improve amino acid availability during time of reduced intake.

Feed Additives and Supplements

Heat-stressed cows lose significant amounts of sodium, potassium, and bicarbonate through increased sweating and respiration. Supplementing the diet with additional electrolytes, via raising the dietary DCAD via potassium and sodium bicarbonate, can help maintain acid-base balance and improve hydration status. Other additives that do not affect dietary DCAD and still combat summer heat stress effects would be osmolytes, vasodilators, and antioxidants. These products support thermoregulation and improve nutrient utilization.

Management Strategies

I would be remiss to not mention that cooling practices/systems are a critical part of reducing summer heat stress. Simply, barns with ample fans and sprinklers will have a greater impact on mitigating heat stress than any dietary strategy. In addition to cooling systems, managing the other resources is critical. Increasing access to clean water space and maintaining optimal feed availability via more frequent feed push-ups will help counteract decreased intakes and altered meal patterns.

Consider The Options

There are several choices when it comes to mitigating summer heat stress. By increasing energy density, adjusting carbohydrate and protein sources, and utilizing certain feed additives, producers can help reduce the loss in milk production. With elevated temperatures in the forecast, now is the time to evaluate our strategies for summer heat stress.

 

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