 This study aims to quantify the area of maximum temperature area of Tmax on the lateral surface of horses and foals using two new approaches to compare the areas of Tmax between horses and foals and to evaluate the struggles of foals with thermal homeostasis. The results indicate that the proposed methods provide a common quality in the thermogram evaluation of foals and adult horses but further research is necessary to determine their diagnostic application. This article was authored by Maugorzata Masco, Marta Borowska, Ursula Sikorska, and others.