The infrared thermography technology is capable of producing an image that portrays the thermal mapping of bodies. Since then, all matter with a temperature above Absolute Zero (-273 °C) emits electromagnetic energy due to the internal Abstract Infrared thermography is a safe technology for diagnostic imaging that preserves welfare and does not emit ionizing radiation. This paper aimed to report the principles of infrared thermography formation and cautions on imaging acquisition with sheep illustrations. This technique is based on capturing infrared electromagnetic energy from the matter molecules, proportional to the increase in temperature. The capture of images, not just in sheep, must obey technical criteria to avoid interpretation errors of the thermograms. Direct exposure to solar radiation, humidity, manipulation of the examined area, time of day, proper use of equipment, and the manifestation of certain behaviors can hinder the interpretation of the findings. Infrared thermography is a tool that helps practitioners because it provides practicality, safety, and accurate data.