Written by Steven M. Haugen, DVM, Courtesy of AAEP
The body maintains its normal temperature in hot weather by moving heat through the muscles and out through the skin. Blood also removes heat as it circulates through the body and releases it through lung tissue, skin and expanding blood vessels. This is why our own vessels and the horse’s blood vessels may appear larger and more distended during hot weather.
This serves to cool the skin as it evaporates. Horses that cannot sweat will usually overheat very rapidly, even in cooler weather with a small amount of exercise. Other factors may increase heating the body other than just outside temperature.