26. April 2021

Heat stress is a problem in cattle. Why?

Most of us prefer the heat to the cold – but a really warm and humid summer’s day can also be really uncomfortable as you just feel drowsy and often lose your appetite. Mostly you just want to sit in the shade and drink something refreshing. Not surprisingly, cattle feel this way too. Over a longer period of time hot weather can cause significant problems for cattle – and for you as a farmer too.

Usually, the cattle can manage the problem themselves and regulate their body temperature. But the thermal regulation via sweat glands is not always functional and doesn’t allow effective regulation of body temperature. Heat stress in cattle occurs when the animals generate and absorb too much heat – more heat than they can easily get rid of by respiration and sweating.

When the sun is out and the temperature is high the cow will tend to reduce feed intake to regulate its body temperature, because the fermentations that take place in the rumen are a source of internal heat release. A reduced intake of feed naturally leads to a drop in milk production. Heat stress also leads to a high variability in rumen pH and a higher risk of acidosis.

Furthermore, heat stress can cause:

  • a decrease in the buffering capacity of the saliva (panting).
  • a decrease in milk fat content
  • an increase in the number of cells

Heat stress is a problem that can have significant costs – both health related and financial. But how do you know it’s happening before it’s too late?

Heat stress can occur even with low temperature
Heat stress cattle figur

These are the symptoms of heat stress in cattle – take notice!

As mentioned, you will see a lower feed intake as feed conversion develops heat and requires energy. The cow will also get up and search for either a water tub or a place where there is air to cool it down. A cow drinks close to double the amount of water if it is heat-stressed.

The cow will also redirect some of the blood flow from the tissue around the stomach and internal organs to the skin to dispose of the heat. The reduction of the blood flow means that there is less oxygen and energy available to the cells around the intestinal tract. This will cause the barrier between blood vessels and the intestinal tract to weaken, which can lead to the condition called "leaky gut".


Advice on heat stress

There are several important steps and countermeasures that you can focus on and implement in order to avoid the problems of heat stress in you herd.

First of all, there is food and water. You have to provide clean drinking vessels and maintain good feed quality. Add acid, if the temperature in the feed rises and increase the energy concentration if necessary. Doing this helps you make sure that your cattle gets the nutrients they need and the same amount of energy on a smaller feed quantity.

There are four other important factors:

  1. Keep an eye on the ventilation and make sure to get as much air through the stable as possible. It is especially important to maintain good ventilation around dry cows / calvers that have started the process of softening ligaments and connective tissue in connection with impending calving. They cannot rise and lie down many times a day, as there is a risk of pressure lesions between the pedal bone and the sole. It’s also important to direct air down to the lying cows so that they are cooled and can avoid getting up.

    The most important thing in all stables is transverse ventilation, which draws fresh air into the barn from the outside.

  2. If possible, try to gather the cows in small groups for milking.

  3. By adding FreshFoss, you provide the cow with an extra buffer, which means that the cow can counteract acidosis and get an improved feed utilization. By adding live yeast, the bacteria in the rumen are stimulated, thus entailing that the cow itself increases its feed utilization.