We’ve already experienced the first warm days, and summer is just around the corner. During this period, the risk of heat stress in calves increases rapidly — often with more impact than expected. Calves drink less, are more susceptible to health problems, and may experience reduced growth as a result. This requires extra attention and labour, precisely at a time when time is often limited.
That’s why it’s important to critically assess your calf housing and barn climate before the real heat sets in.
What is heat stress in calves?
Heat stress occurs when a calf is unable to release enough body heat. Young calves are especially sensitive to this. Problems can already arise at temperatures between 20 and 25 degrees Celsius, particularly when humidity is high and ventilation is poor.
Many farmers mainly associate heat stress with dairy cattle, but calves are also quickly affected.
Consequences of heat stress in calves
Heat stress often leads to:
- Lower feed intake
- Reduced milk consumption
- Growth delays
- Increased risk of diarrhoea
- Respiratory problems
- Reduced immunity
- Higher mortality rates
- More work and additional care moments
And especially during busy periods, the first signs are easily overlooked.
The germ factor: heat increases germ pressure
Germs are present in every barn and originate from the environment. In warm and humid weather, bacteria and pathogens have a greater opportunity to develop rapidly. When the germ pressure becomes too high, the calf uses its energy for recovery instead of growth.
Poor ventilation, wet bedding areas, or insufficient cleaning can further increase this problem.
That is why easy-to-clean calf pens, good air circulation, and dry housing are essential during warm periods.
Lower germ pressure starts with:
- Good ventilation without drafts
- Dry and clean resting areas
- Easy-to-clean calf housing
- Sufficient air circulation
A stable environment keeps germ pressure low and helps the calf stay healthy. Drafts, heat, cold, or stress all cost the calf energy and increase its susceptibility to germs already present in the environment.
Especially during warm days, the environment should support the calf rather than create additional stress.
Good ventilation is the foundation
A good barn climate is the most important step in preventing heat stress. Warm air, moisture, and ammonia must be removed quickly — without creating drafts.
Practical tips for better ventilation
- Check whether air inlets and ridge openings are unobstructed
- Ensure sufficient air exchange without drafts
- Use natural ventilation whenever possible
- Prevent warm stagnant air in the calf pens
Many heat-related problems occur because the barn retains heat during the day. Dark roofs and poorly insulated barns in particular create additional stress for calves.
Why an insulated roof helps
An insulated roof provides:
- Less heat build-up during the day
- A more stable barn climate
- Fewer temperature fluctuations
- More comfort for the calf
- Less stress during hot days
The calf: a healthy calf shows it immediately
Is your calf housing in good condition? Your calf will show it.
A healthy calf:
- Grows well
- Is active
- Eats well
- Drinks well
- Looks healthy
- Has calm breathing
Calves suffering from heat stress, on the other hand, often become lethargic, drink less, and are more susceptible to diseases.
Signs of heat stress in calves
Pay extra attention during warm days to:
- Rapid or shallow breathing
- Panting or breathing with an open mouth
- Reduced drinking or eating
- Warm-feeling ears
- Lying down more and showing less active behaviour
The earlier you recognise the signs, the smaller the impact will be.
Extra tips to prevent heat stress in calves
With a few practical adjustments, you can already make a big difference.
Practical measures during hot days
- Always provide fresh drinking water
- Refresh water more frequently during warm periods
- Feed calves during the cooler parts of the day
- Limit stressful activities during hot weather
- Keep bedding areas dry
- Carry out at least one extra inspection round
- Check ventilation daily
Ease of work also plays an important role. The easier systems are to use and clean, the easier it is to manage during busy periods.
Good calf housing helps prevent heat stress
Strong, durable, and well-designed calf housing makes daily work easier while also supporting calf health.
Key features of good calf housing:
- Good ventilation without drafts
- Strong and durable pens
- Easy to clean
- Mobile solutions where needed
- Practical doors and locking systems
- Comfort for both people and animals
- Long-lasting quality and reliability
Our solutions combine the three pillars — the germ factor, the environment, and the calf — resulting in visible improvements in calf rearing.
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Once the real heat arrives, it is often already too late. By paying attention now to ventilation, germ pressure, drinking water, and calf housing, you can prevent many problems later in the season.
Healthy calves grow better, require less labour, and ultimately deliver better results.
Would you like to know how to better prepare your calf housing for warm periods? Feel free to contact us for practical advice on housing solutions for the youngest calves on your farm.