Top Tips on Managing Heat Stress in Dairy Cows

As global temperatures continue to rise and weather patterns change, heat stress is becoming more common. Those with livestock are the most affected with dairy farmers at the top of the list.  

Although heat stress is associated with high temperatures, cows can develop heat stress at much lower temperatures in humid conditions like in the UK.

High humidity means that any moisture on the cows’ skin cannot dissipate, preventing evaporative cooling.

There are some quick wins that you can make to reduce heat stress in your herd, though some changes will need longer-term planning.

What is heat stress?

Like in humans, heat stress happens when a cow’s temperature goes above its normal range.

Cows can sweat but they have fewer sweat glands, and the ones that they have aren’t as effective as most other mammals[1]. This means that cows cannot cool themselves as effectively as humans can.

Heat stressed cows will:

• Become lethargic
• Stand with bowed heads
• Huddle in shaded areas
• Pant
• Produce less milk
• Eat less food
• Be pre-disposed to other illnesses, poor fertility and lameness

Tips to reduce heat stress

Although you can’t change the weather, there are steps that you can take to improve your cows’ comfort during heat waves.

Management tips to reduce heat stress

• Our top tip is to increase the amount of natural ventilation going through the building – for example, can fixed cladding on the sides of your building be removed for the summer.
• Reduce the stocking density in sheds to lower the amount of heat and water vapour created by the animals as they ruminate and respire
• Ensure that there is enough trough space for 10% of the cows in your herd to drink at once. The AHDB recommends 10cm of trough space per cow
• Move animals during the coolest parts of the day, like the early morning or late evening
• Feed cattle in the early morning and later evening to encourage better rumen fill
• Increase the energy density of the feed, while reducing the amount of stemmy forage

Long-term strategies to reduce heat stress

• When building new housing, or replacing shed roofing, choose a white roof to reflect solar heat
• Add cooling mechanisms to the housing, such as a sprinkler or fan system:
  • Sprinkler systems should produce a steady stream of fine mist to avoid wetting bedding
  • Positive pressure tube ventilation systems like Galebreaker’s VentTube Cool, target fast moving air to the cow, to produce a cooling effect on the animal to increase cow comfort.
• Variable ventilation, either through Rollerscreens or Galebreaker VVS side curtain system to the sides of sheds and buildings. The automatic control system continually optimises the ventilation inside the building using temperature, wind speed, wind direction and rain sensors to maximise ventilation.

[1] https://www.vitaplus.com/starting-strong-calf-care/ask-the-expert-do-calves-sweat