Applicability of the auricular temperature for the assessment of body temperature in healthy large and small domestic species, in a normal metabolic state and in controlled environmental conditions.

This study investigates the accuracy of using an infrared thermometer to measure auricular (ear) temperature as an indicator of body temperature in healthy large and small domestic animals, compared with the ‘gold standard’ practice of measuring rectal temperature, under controlled environmental conditions. The findings reveal that there was no significant difference between the temperatures recorded in the left and right ears of cats, dogs, and horses, yet the rectal temperatures were generally found to be higher than the auricular temperatures, with these differences being clinically relevant especially in horses.

Study Methods and Initial Findings

• The research involved measuring the body temperature of three different species, specifically eleven healthy mixed bred cats, eleven Rottweiler dogs, and eleven Italian saddle horses.
• The body temperature of the participants was measured using two methods. One involved using an infrared thermometer to measure the auricular temperature, and the other involved using a digital thermometer to measure the rectal temperature.
• The findings from a two-way analysis of variance (ANOVA) indicated a statistically significant difference between these two methods, with the rectal temperature being higher than the ear temperatures, regardless of whether the left or right ear was measured (P<0.001).

Comparative Analysis Across Species

• On comparing the temperatures between species, cats and dogs were found to have a statistically higher auricular and rectal temperature compared to horses (p<0.001 and p0.05).
• The Bland-Altman test, a method to compare two clinical measurements, was used to analyze the agreement between auricular and rectal temperatures for the three species. It revealed that the average difference between these two measurements was 1.6 °C for cats, 1.4 °C for dogs, and 3.3 °C for horses.

Correlation Findings

• The study found a positive correlation (r=0.78) between rectal and auricular temperatures in dogs, indicating that as the rectal temperature increased, the auricular temperature also tended to increase.

Conclusions

• The findings imply that while the auricular temperature measured using an infrared thermometer may be useful in monitoring the body temperature in healthy dogs kept in controlled conditions, it must be noted that this is normally about 1.5°C lower than rectal temperature, the latter being the gold standard for measuring body temperature.