Observations on human beings which indicated that heatstroke was not caused by arrest of sweating but by excessive accumulation of heat in the body permitted development of experimental models in dogs. Examined were 53 mongrel dogs exposed to one of the following: external heat and physical exertion, external heat alone, or physical exertion alone. Dogs whose rectal temperature exceeded 43 C (109.4 F) showed clinical, hematological, biochemical, and anatomopathological manifestations, which were identical to those of heatstroke in man; none of the dogs with rectal temperature below 43 C showed signs of heatstroke. The severity of the heatstroke was positively correlated to the level of the maximal temperature and to its duration. These findings strengthen the concept that heatstroke is caused by the noxious effect of excessive body temperature on the tissues.
Shapiro Y, Rosenthal T, Sohar E. Experimental HeatstrokeA Model in Dogs. Arch Intern Med. 1973;131(5):688–692. doi:10.1001/archinte.1973.00320110072010