This study presents a geometric and mathematical modeling approach to analyze the propagation of low-intensity laser radiation (LILR) in the cervical region of sheep. A comprehensive geometric model was developed to simulate the laser's interaction with biological tissues, focusing on the cervical area, particularly the thymus. The simulations indicated that the intensity of laser radiation on the external neck surface was about 200 times lower than that experienced by the thymus, primarily due to tissue absorption effects, resulting in a maximum energy reach of 140 W/m2 at the thymus. Thermal modeling suggested that safe irradiation durations ranged between 20–30 s, with expected surface temperatures rising to approximately 42 ℃. These findings illustrate the potential of mathematical and computational modeling in understanding LILR effects on biological systems, thereby informing safe and effective application in veterinary practices.