A dairy cow has only 24 hours in a day. In an average commercial Danish herd housed in free-stall barns, cows spend around 10.8 hours lying down, 5 hours feeding, 2.9 hours standing in alleys, 2.9 hours standing in stalls, 1.9 hours at the feed bunk and 0.5 hours in milking. This daily time budget can vary significantly depending on housing conditions, management practices and the cow’s physiological status.

Lying behaviour is one of the cow’s highest priorities. If cows are prevented from lying down, both behavioural and physiological stress responses may occur. For example, growth hormone levels may decrease and development can be impaired. When total lying time falls below 10 hours per day, it may suggest that the cow does not have enough opportunity to rest and may be under stress.

This issue becomes even more important in high-producing dairy cows. As milk yield increases, the cow requires higher energy intake. This can partly be supported by increasing the energy density of the diet, but there are limits because rumen and digestive health must be protected. High-producing cows also need more time to feed, leaving less time available for other activities such as lying down.

Under time pressure, cows may choose to preserve lying time by giving up part of their feed intake. This shows that restrictions on high-priority behaviours can negatively affect feed consumption and milk production. Reduced intake may later contribute to body weight loss and increase the risk of diseases that affect performance.

Access to resources is another major factor. Barn construction costs may limit the available space per cow and the number of feeding, drinking and resting places. When cows have to compete for feed, water or lying areas, social stress can increase. This may reduce welfare and interfere with the efficient conversion of feed into milk.

Group changes also influence cow comfort and productivity. Dairy herds have a social hierarchy based on dominance relationships between animals. In larger farms, cows are often moved between groups to optimize feeding or monitoring. However, these changes can increase aggressive interactions, raise the risk of injury and reduce lying time. Some studies have reported reduced milk yield for several days or even weeks after regrouping. More space and easier access to resources are expected to reduce these negative effects.

Lying area availability is particularly important. Several studies have shown that when stocking density increases to more than one cow per stall, lying time decreases, aggression rises and abnormal behaviours may become more common. Cows may even lie in alleys, which can increase the risk of poorer performance outcomes. Short lying time and long standing time at the feed alley can also increase the risk of claw disorders.

Feed access must also be carefully managed. If feed is offered in restricted amounts, there should be at least one feeding space per cow. Otherwise, some cows may not be able to access feed at all. Even when cows have free access to feed, competition at the feed bunk can increase displacements and reduce feeding time.

Prof. Munksgaard notes that many farmers still have limited knowledge of cows’ time budgets. However, tools are now available to record lying behaviour automatically on farms. These technologies may help producers assess how management changes affect cow behaviour, such as changes in diet energy density or moving from twice-daily to three-times-daily milking.

For high-producing dairy cows, waiting time before milking should be limited as much as possible, and barn design should provide easy access to feed, water and resting areas. If lying time drops below 10 hours per day, it may serve as an early warning that cows are not getting enough rest.

For dairy businesses, investing in cow comfort is not only a welfare decision. It is a productivity strategy that protects feed intake, milk yield and long-term herd performance.