Nychthemeral rhythm of vaginal temperature in captive red deer (Cervus elaphus) during the spring season recorded via the iButton®

Abstract

ABSTRACT The study aimed to characterize the daily vaginal temperature pattern of captive red deer (Cervus elaphus). Ten adult female red deer received a vaginal implantation of an automatic temperature recorder (iButton®) attached to a CIDR-G device. The   ambient and black bulb temperature, sunrise and sunset times were also registered. The daily vaginal temperature exhibited a significant rhythmic pattern (p < 0.05), with a mesor of 38.8 °C and an amplitude of 0.40 °C. During the diurnal phase, increasing vaginal temperature values were observed, while during the nocturnal phase, decreasing values were recorded. The bathyphase and the acrophase were recorded at 7:00 AM and 7:00 PM, respectively. The vaginal temperature exhibited a positive correlation     with the ambient (r = 0.80, r2 = 0.64) and black bulb temperature (r = 0.40, p < 0.05). In concludsion the vaginal temperature of red deer exhibited a nychthemeral pattern, with increasing values during the diurnal phase and decreasing values during the nocturnal phase.