Summer is here and with it comes high temperatures, high humidity, and increased chances of heat stress. According to a 2019 Foundation for Food and Agriculture Research study, the US dairy industry experiences $1.5 billion in losses to heat stress annually. With afternoon humidities of 60-70%, and temperatures at 75-77°F, cows may already begin to experience the effects of heat stress – that’s a temperature humidity index (THI) of 74. Higher temperatures can impact herds, potentially decreasing performance, production, and profit.

Incorporating proper fans and soakers, adequate water and feed, and providing a proper nutrition are beneficial steps to combat the hot summer months. Here are three tips to manage heat stress in dairy herds.

Fans need to be clean and should generate at least 5mph wind over the back of the cow. Use a wind speed meter to detect good air movement and dead areas, especially where cows congregate. Add in soakers on the feed bunk and in the holding pen to apply water to the back of the animal. In humid climates, which include much of the US, water should be applied as a “soak” and not a mist. Maximize equipment performance by regularly monitoring and maintaining fans and soakers.

Calves, like human babies, thrive on consistency in their nutrition program. We want to feed them the same volume and temperature of the same product at the same time every day. Both whole milk and milk replacer can work well, depending on the farm’s management system. With milk replacer, it’s key to follow label directions specifically regarding water temperature for reconstitution, and to mix to the same total solids every feeding. When feeding whole milk, it’s important to monitor total solids and supplement as necessary to keep a consistent product for the calves. As we work toward the goal of transitioning calves from a milk-fed diet to a grain diet, all changes should be gradual, and we should not make more than one change at a time.

Higher temperatures can negatively affect milk production and milk fat yield, due in large part to heat stress-induced pH decrease in the rumen and leaky gut. Although it is vital to provide proper heat abatement strategies, there are also feeding strategies that may assist in reducing lost performance. Incorporating effective feed additives could help promote gut health, immune strength, and overall wellness. Healthy cows perform better, and a healthy gut can help cows manage the heat. Ultimately, this can result in greater profitability on the farm. Consult with your nutritionist about what ration changes might be appropriate for warmer temperatures, including the addition of products to optimize rumen health.

With summer temperatures reaching 80-90°F, dairy cows will be feeling the heat. When you incorporate these three management tips, your herds have a better chance of staying healthy and productive.