The effect of a shade structure on the behaviour of lactating Friesian cows in open camps (dry lots) was determined over two consecutive summer periods. The daily activities of cows were observed and recorded on 9 separate 24-h periods. Shade cows spent more time (P < 0.05) feeding during the day than no-shade cows, while there was no difference in feeding time at night. More than 80% of the cows in both groups started to eat directly on returning from the milking parlour. Feeding lasted for approximately 2.5 h during the morning, whereas the first feeding period in the afternoon was shorter (probably owing to high ambient temperatures) and cows (60%) ate again at 19:00. No-shade cows spent more time (P < 0.05) standing during the day than shade cows and they also tended to crowd around the water trough. Shade cows tended to spend more time (P < 0.10) lying down (mainly in the shade) to ruminate or to sleep than cows without access to shade. Different behavioural patterns indicated responses by cows specifically aimed at alleviating heat stress during the day.