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Don’t sweat it: Three strategies to protect dairy calves from heat stress

July 13, 2017

The impact that heat stress can have on a herd, as we all know, can be substantial. When looking at a lactating herd, it is critical to find ways to minimize the effects of heat. But one vital area of the farm that is affected by heat is sometimes overlooked: calves can be extremely susceptible to higher temperatures due to their smaller body mass and higher respiration rate.

Calves and lactating cows experience heat stress at different levels. For a mature lactating animal, the level at which they begin to experience heat stress is at around 60 degrees Fahrenheit and is lower in humid environments. In contrast, calves start feeling heat stress around 75-80 degrees Fahrenheit. In the summer sun, calves look for relief in their hutches, but sometimes the hutch environment can be even hotter and more humid than the outside environment.

By managing the following three key areas, producers can ensure that their calves stay cool and healthy during the hottest time of the year.

Drink up: Keep calves hydrated

Though it might seem obvious, ensuring calves have an adequate water supply that is fresh and clean can be a key factor in helping to prevent dehydration. Dehydration can be particularly dangerous during times of gastrointestinal stress, which can hinder a calf’s rate of recovery.


Water acidifiers have been shown to increase water consumption because they make the water more palatable to the calves, which encourages them to drink more.


Shoo, fly  don’t bother the calves!

Hot temperatures go hand in hand with flies. It is extremely important to control flies in the calf’s environment, as flies are a main offender when it comes to transferring dangerous bacteria throughout the herd. Illnesses such as pink eye are known to be spread by flies. Recent research has also shown that flies can be carriers of some strains of Salmonella, which can show up later in life as a cause of mastitis at first lactation.

Common fly control methods include an Insect Growth Regulator (IGR) in the feed as well as treating and spraying around hutches with chemicals labeled to assist in fly control.

Easy, breezy temperature maintenance

Adequate ventilation is important for calves, especially if they are kept inside an enclosed area or barn. Some operations may have a more serious ventilation issue when using automatic feeders because the bedding can be more prone to moisture.

Ensuring the bedding remains clean and dry is critical to calf health and longevity. As temperatures rise, ammonia levels tend to rise as well, and wet bedding can pose a serious threat to calves as a result. Utilizing an ammonia binding product can be helpful.

De-Odorase®, a product from Alltech, is commonly utilized in calf barns to control ammonia issues.


Adequate ventilation is also important in the hutch. One key component to hutch ventilation is keeping vents open during the day, as hutches can get too hot if vents are closed. What many people don’t think about in the summer, though, is that hutches can also get too cold on cool evenings if the vents are not closed at night. This is particularly concerning in the summer because usually less bedding is used during this time, and a cold front can be hard on the less protected calves, especially when they are younger.

Heat stress can affect herds in many ways. Herd longevity and the future of operations depend on the health of calves, who rely on farm owners and managers taking the necessary steps to ensure they remain healthy during the summer. 


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