Horses standing in the sun without shade or breeze will very rapidly accumulate heat. Even at rest, once the temperature reaches above 37 degrees a horse’s core temperature will rise unless it is actively cooled.
Camden Equine Centre
From the Blog
Liver disease occurs commonly in horses. Classical clinical signs of liver disease in horses are vague but generally include jaundice (yellowing of the whites of the eye), weight loss, mild diarrhoea and in severe cases, neurological signs and uncontrolled bleeding tendencies.