Could the different estrus periods significantly affect body temperature on clinical examination in bitches?

Clinical examination is essential to make a differential diagnosis list, and body temperature measurement is an indispensable part of the clinical examination. Throughout the estrus cycle, body temperature may fluctuate high enough to affect the clinical examination results. Aim of this study, whether there were any differences between the different estrus periods, body parts (rectal, intravaginal and corneal), and methods (contact thermography and infrared thermography) in regard to temperature in bitches. The animal material of this study consisted of 61 healthy, non-pregnant, non-sportive bitches (2.78 ± 0.22 mean years of age; mean weight 23.81 ± 1.61kg) of different breeds. Corneal temperature measurement results were found the least constant and significant differences were observed between different estrus periods except in the anestrus period. Rectal temperature (RT) measurement results were the most constant. However, in ANOVA analysis, significant differences were observed between the different estrus periods, and the difference between the anestrus and diestrus periods was very close to 0.5 °C. Although, in the Bland-Altman plot analysis, the agreement was observed only between rectal and intravaginal temperature (p: 0.572, r2: 0.70), the limits of agreement were not clinically acceptable. In conclusion, neither corneal temperature measurement with infrared technology nor intravaginal temperature measurement should not be an alternative to RT measurement, and RT measurement results should evaluate carefully considering the estrus period.