Use of thermal imaging for identification of foot lesions in dairy cattle

Abstract

The objective of this study was to investigate the use of infrared thermography (IRT) for detection of foot lesions in dairy cattle. Thermal images of the rear feet of 139 lactating dairy cows were taken with a thermal camera and evaluated using imaging software. Foot lesions identified in the study included white line disease (WLD), sole ulcer (SU) and digital dermatitis (DD). Temperatures at the coronary band (CBT) and the skin (ST) were recorded. Cows were scored for locomotion on a scale of 1-5 (1=normal and 5=severely lame). CBT was higher for all types of foot lesion (34.1 +/- 2.3, 33.8 +/- 1.6 and 33.1 +/- 1.6 degrees C for WLD, SU and DD, respectively) than for healthy (32.6 +/- 1.9 degrees C) feet. ST was higher only for WLD (33.2 +/- 2.0 degrees C) compared to healthy feet (31.5 +/- 1.7 degrees C). T (temperature difference between CBT and ST) was higher for SU (2.1 +/- 0.8 degrees C) than healthy feet (1.1 +/- 0.9 degrees C). Locomotion scores (LSs) were similar between healthy cows (2.2 +/- 0.7) and DD (2.4 +/- 0.7) but greater for SU and WLD cows (3.0 +/- 0.9, 3.0 +/- 0.8) than healthy cows. The threshold values established for CBT and ST were 33.5 degrees C (sensitivity=77.8%, specificity=65.2%) and 33.7 degrees C (sensitivity=44.4%, specificity=92.9%) for SU, and 34.4(o)C (sensitivity=28.1%, specificity=88.6%) and 31.8 degrees C (sensitivity=60.7%, specificity=55.4%) for overall lesion, respectively. These results indicate that IRT can be a useful tool for detection of SU, but not WLD and DD. In addition, CBT and T were the best indicators for the detection of foot lesions.