A dairy animal-monitoring system (1) for a herd of dairy animals (3-1)comprises a dwelling space for the herd ofdairy animals, one or more controllable heat stress-reducing means (14) forreducing or preventing heat stress in the dairy animals,and a control system (10, 11) for the dairy animal-monitoring system whichcomprises a subset-determining device for determining orinputting a subset of the herd, an identification system (4, 5) foridentifying the dairy animals from at least the subset, and a heat stress-detectingsystem for detecting a value of a heat stress indicator with a dairy animal ofthe subset. The control system is configured tocontrolling the one or more heat stress-reducing means in several of the dairyanimals, in particular in substantially the entire herd in thedwelling space (2), on the basis of the at least one detected value. Thesubset of the animals are the indicator animals which will showheat stress sooner, as a result of which the control unit will cool down allcows in order to prevent the other animals from developingheat stress before it becomes noticeable. Due to the fact that monitoring nowonly has to be performed for some of the animals, thisis easier, more accurate and more reliable.
