Infrared Thermographic Assessment of Cold Stress and Growth Performance in Romanian Spotted and Romanian Brown Calves

Abstract

Infrared thermography (IRT) represents a non-invasive method for detecting temperature variations on the surface of an animal’s body. By capturing infrared radiation emitted by the animal and converting it into thermal images, IRT enables the early identification of health and physiological disturbances. The aim of the study was to test the ability of Romanian Spotted (RS) and Romanian Brown (RB) calves to adapt to cold thermal stress. In this respect, 20 calves (10 RS and 10 RB) were included, having recorded the dynamic of the body temperature at the nose (BTN) and eye (BTE) and average daily gain (ADG) according to environmental temperature (ET) and calves’ breed. Data were collected between January and March 2025, being expressed as average and standard deviation. Thermal images were collected twice daily, during the morning and afternoon, from a distance of 0.5 to 2 meters, using a FlirOne mobile infrared camera. Comparisons were performed using one-way ANOVA, with the categorical factor being the calves’ breed. Decisions about the acceptance or rejection of statistical hypotheses were made at the 0.05 level of significance. No significant differences (p>0.05) were observed for BTN (23.24±3.14 ^°C vs. 24.3±2.86 ^°C for RS and RB) or BTE (33.4±2.44 ^°C vs. 33.9±2.97 ^°C for RS and RB). The ET proved to be an influential factor for both BTN and BTE. No significant difference was recorded for ADG according to the calves’ breed (0.818 vs. 0.784 kg/day for RS and RB, p>0.05). ET significantly influenced ADG in both breeds, with a value of ADG of 8.84% from January to February compared to February to March (35.15%, p≤0.001). In conclusion, both breeds included in the study possess comparable abilities to adapt to their environment.