24-hour measurements show the importance of a consistent rhythm for rumination, growth and health.
To gain insight into the behaviour of calves, Topcalf conducted 24-hour measurements. Activity, rumination behaviour, feed intake and rest were monitored day and night. The conclusion is clear: calves live according to a fixed day–night rhythm. This rhythm has a direct influence on rumen development, feed utilisation and growth.
The day–night rhythm of calves in focus
The measurements show a logical but important pattern. During the day, calves are more active. They stand up more often, visit the feed fence and clearly respond to fixed feeding times. Around these moments, visible peaks in activity and feed intake occur.
When evening falls, the pattern changes. Calves lie down for longer periods and at the same time rumination activity increases. The feed that was consumed during the day is processed during the night. The natural rhythm of calves becomes clearly visible here (see Figure 1).
Figure 1: Rumination activity in relation to feed visits during the day. Feed delivery at 07:00 and 16:30 results in clear peaks in feed visits. In the following period, rumination activity increases, indicating active rumen processing between feedings.
How does rumination support rumen development?
Rumination is essential for a well-functioning rumen. When a calf (or cow) ruminates, it produces saliva. This saliva helps keep the rumen stable and prevents acidification. As a result, the feed that has been consumed is used more efficiently and rumen development is supported.
After the last feeding, rumination activity clearly increases. Night-time rest therefore directly supports the growth of the calf. Disturbing this rest also affects how the feed is processed.
Fixed feeding times determine the rhythm of calves
The measurements show how strongly calves respond to fixed feeding times. As soon as it is time to feed, they become active. They stand up, move towards the feed fence and become more active. This is exactly what you can also observe in the barn.
After eating, a calm period usually follows. Calves lie down and start ruminating. First eating, then processing — that is the natural daily rhythm of calves.
This shows that fixed feeding times help determine the rhythm of calves. When feeding times vary from day to day, unrest within the group occurs more frequently. Calves stand up more often, rest for shorter periods and ruminate less regularly. A fixed rhythm provides calmness and stability in the barn.
Practical experience confirms: deviations from the rhythm cause stress
Adriaan Beulens, veterinarian at the Veterinary Centre Midden Salland, emphasises the importance of predictability for young calves.
“A calf lives on expectation. When you consistently deviate from the fixed pattern, the calf experiences stress. And stress increases the risk of health problems, including diarrhoea.”
This is particularly important on larger dairy farms, where many calves are fed one after another. Not only the timing of feeding is important here, but also the order.
When an employee starts feeding on the same side of the barn every day, calves learn to recognise this pattern. As soon as they hear familiar sounds, they know what to expect: milk immediately or a short wait. This predictability creates calmness.
If the order is changed on a certain day, this established expectation pattern is disrupted. Calves that normally receive milk first suddenly have to wait longer. This unexpected change creates unrest and increases the stress level in the group — resulting in a greater chance of diarrhoea.
Consistency therefore lies not only in fixed feeding times, but also in consistent routines and working methods.
What does this mean for your farm?
The insights from the 24-hour measurements can be directly applied in practice:
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Work with fixed feeding times
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Keep daily routines as consistent as possible
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Limit disturbances during night-time rest
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Ensure predictability in the feeding order
In the evening, take a moment to observe the group behaviour in your barn. Are many calves lying down calmly and ruminating at the same time? If so, the rhythm is functioning well. If you notice a lot of unrest or scattered activity, it may be useful to review your daily routines.