Furthermore, daily dry matter intake (of PMR) and milk yield on herd basis as well as respiration rate and rectal temperature of 10 selected cows were measured as indicators for heat stress.


 During the heat period hyperthermia (> 39° C) was frequently recorded in lactating cows (up to 100 %).


 As severe and long-lasting effects of heat stress on health and performance of dairy cows are well described in the literature, especially the temporarily high prevalence of hyperthermia should be taken seriously.  Under these circumstances, differentiating between hyperthermia and fever is of special importance for veterinary practitioners.
THERM