Use of thermography in pigs : relationship between surface and core temperature

This study aims to assess the correlation between surface temperature estimated by infrared thermography and core temperature measured with rectal thermometer in weaning and fattening pigs. A total of 108 pigs were used in this study. Thermal images of the eye of each animal were recorded with a thermal imaging camera, rectal temperatures were measured using a calibrated digital thermometer. The average rectal temperature was 38.9 +/- 0.4 degrees C (MIN = 37.9 degrees C; MAX = 40.1 degrees C) and the average eye temperature was 36.7 +/- 0.1 degrees C (MIN = 34.8 degrees C; MAX = 38.8 degrees C). Our results showed that the mean eye temperature estimated by infrared thermography was significantly correlated (r = .581, P < .01) with rectal temperature. The correlation was significant and strong for weaners (r = .739, P < .01), significant although weak for fatteners (r = .236 P < .05). Thermography could be a valid method to estimate the core temperature of pigs under farm condition.