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Heat stress also possible at lower temperatures

Heat stress also possible at lower temperatures

The weather is getting better, which means heat stress is once again on the agenda. But did you know that cows can suffer from mild heat stress as early as 18 degrees Celsius? In this article, we tell you exactly how this can occur and how it can affect your cows.    

Heat stress in cows occurs when the ambient temperature exceeds the cow's thermoneutral zone. This is the ambient temperature at which the cow does not need to use extra energy to regulate her body temperature. In cows, the thermoneutral zone is between about 5°C and 20°C, depending on age, breed, weight and production. 

When the ambient temperature rises above the thermoneutral zone, the cow has to use more energy to regulate her body temperature, giving her less energy to spend on growth, reproduction and milk production. 

The influence of humidity

Humidity plays an important role in the development of heat stress in cows. High humidity makes it harder for cows to dissipate their body heat through the evaporation of sweat on the skin. This is because the air becomes saturated with water vapour, making sweat less likely to evaporate and preventing the cow from cooling down effectively.

In addition, cows regulate their body temperature largely by panting. When humidity is high, it becomes more difficult to breathe properly. This slows down the absorption rate. 

Thus, at high humidity and high temperatures, heat stress in cows can be even more severe than at high temperatures and low humidity. It is therefore important to monitor humidity in addition to ambient temperature and take measures to lower it if necessary.

To reduce humidity, as a farmer you can use various techniques such as installing fans or creating shaded areas. Adjusting feed rations and giving extra water can also help reduce the impact of heat stress on cows.

What can cows suffer from?

Symptoms of heat stress in cows include increased breathing, increased heart rate, increased saliva production, reduced feed intake and reduced activity. This often leads to a decrease in milk production, (rumen) acidosis, reduced fertility and immune response. The latter, in turn, can lead to mastitis, claw disorders and higher failure rates. To maintain milk production, good water, dry matter and nutrient intake are essential during this period.

The role of glucogenic energy

Glucogenic energy is needed to supply energy to the cow's brain, organs and nervous system. When glucogenic energy is in short supply, the body will draw on other sources of energy, such as fats and proteins, to make up the shortfall. This process can lead to the accumulation of ketone bodies in the cow, making it much harder for the liver to function efficiently. 

The accumulation of ketone bodies reduces the cow's appetite, further reducing glucogenic energy levels. This can create a vicious cycle, where heat stress and reduced glucogenic energy reinforce each other's negative effects. Besides maximum cooling, it is therefore important to maximally stimulate the cow's intake of moisture and nutrients. 

Want to know more about heat stress in cows or make an appointment with our specialists to see how we can optimise this on your farm? Feel free to contact us.

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Martijn Kirghof
Martijn Kirghof
Specialist
I would be happy to tell you more about TheTransitionCompany and what we can do for you. Please feel free to contact me.
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