Comparison of daily rhythm of rectal and auricular temperatures in horses kept under a natural photoperiod and constant darkness

The aim of this study was to assess the accuracy of auricular temperature (AT) recording in the determination of body temperature as well as rectal temperature (RT). For this purpose we compared RT and AT in five clinically healthy horses. Data collections were performed every 3 h over 2 different 24 h photoperiods, 13/11 light/dark cycle and constant darkness. Repeated measures multifactor analysis of variance (MANOVA) was applied to determine a statistical significant effect of time of day, side of temperature collection and photoperiods on AT and RT. Our finding showed a significant effect of time of day on the temperature values recorded and an influence of side of temperature collection. RT values were higher of about 4 °C than the AT values, and the pattern of the two temperatures was not comparable. A daily rhythmicity of rectal temperature was observed. Auricular temperature no showed daily rhythmicity in both periods of monitoring. On the basis of these findings AT does not reflect body temperature as well as RT in horse.