Comparison of axillary and inguinal body temperature to rectal temperature in healthy guinea pigs (Cavia porcellus)

Background: Core body temperature is a crucial health parameter. Temperature aberrations can indicate certain infectious or inflammatory disorders, influence clinical management decisions, and serve as a prognostic indicator for patient recovery. Historically, rectal temperature measurements have been utilized in small companion zoologic animals. However, there is a growing interest in less invasive methods including auricular and axillary measurements to determine core body temperature. Methods: Temperature measurements were obtained from three locations (axillary [AT], inguinal [IT], and rectal [RT]) in a randomized order and performed in duplicate in 40 healthy guinea pigs during a handling period spanning less than 3 minutes. Results: Obtaining RT was safely performed in all animals. IT (mean = 38.1°C) and AT (mean 38.5°C) were significantly lower than RT (mean = 38.8°C; P < 0.0001 and P = 0.0001, respectively). Constant and proportional error was observed between RT and IT, but not between AT and IT as well as AT and RT. Conclusions and clinical relevance: Based on the clinically significant differences in difference of the mean, wide limits of agreement and outlying data points on Bland-Atman analyses, RT should remain the clinical gold standard to measure core body temperature in guinea pigs. Obtaining RT in the guinea pig is safe and causes no overt harm and could add additional information to a veterinary assessment.