Infrared thermography used to measure physiological variation of the coronary band temperatures in horses

Introduction: The coronary band (Cb) is commonly investigated during the antidoping procedures as indicator of abuse of substances to influence performance. The purpose of this study was to investigate temperature (T) changes on coronary band to understand the normal variations in equine thermal patterns using Infrared thermography (IRT) Material and methods Six healthy warmblood horses (geldings) (5 to 10 years old) (medium BW 555±73 kg) were included in the study. Horses were kept at International Center of Horse (Druento, Italy). The animals were fed with maintenance ration based on INRA requirements composed by 80% first cut meadow hay and 20% of oat. The feeding plan was divided in three meal(m) a day: the same amount of oat was given at 08:00am- 01:00pm and 06:00pm; hay at 08:00am and 06:00pm. IRT images taken from the dorsal view of forelimb on Cb and rectal temperatures (RT) were recorded immediately before the morning meal (mm), noon (nm) and evening (em) and after 10 minutes (IR10), 60 (IR60), 180 (IR180) and 240 (IR240) after each meal and every two hours during the night. The max T within the area of interest was recorded. After the normality was checked the mean changes Cb and RT with time was compared using repeated measure ANOVA; Bonferroni post hoc test was used to identify differences (p<0.05); Pearson correlation was also performed between RT and Cb. Results RT increased from a value of 37.5±0.24mm to the value records at IR60nm (37.9±0.19 p<0.01), reaching the max value 37.9±0.19 for IR240em (p<0.01) and returns to basal values at 2:00am. No variation was identified comparing the T recorded before and after meal. Cb T increased immediately after the meal from a value of 32.7±0.62 mm to IR10mm(33.8±0.37 p<0.05); this increase persisted during day and night reaching max value at IR10em (35.1± .65). RT was correlated with Cb p<0.01) . Conclusion RT variations recorded were less than 0.4°C; Cb variations recorded were less than 2.4°C. The values recorded seems to be influenced not only by the circadian rhythm of body T but also other metabolic activity such as the meal. Identify the standards of normality could help the practitioner to identify horse’s with abnormalities or hypersensitizing substances abuse.