Surface temperature in different anatomical regions of ewes measured by infrared thermography

The objective of this study was to evaluate the variation of surface temperature through infrared thermography (IRT) in different anatomical regions during the estrous cycle of hair sheep. The estrous cycle of 20 Santa Ines hair breed ewes was synchronized and, during this synchronization period (15 days), environmental conditions (temperature, humidity and wet-bulb globe temperature) and body temperatures were evaluated. The temperatures of the rectum and vagina were measured with a digital thermometer and the surface temperature of the anus, vulva, muzzle, left eye and left ear were measured with an infrared thermal camera. The mean, standard deviation, regression and correlation of each temperature of each anatomical region were evaluated regarding the estrous cycle. The eye was not a good anatomical region to measure the temperature variation during the estrous cycle (R-2 = 0.011, p > 0.05). The vulva was the region with greatest potential for evaluation of surface temperature variation with IRT during estrus synchronization (beta = 0.0805; R-2 = 0.767, p < 0.001).