Detection of digital and interdigital dermatitis in Holstein Friesian dairy cows by means of infrared thermography

Diseases of the bovine foot are a serious threat to dairy cows welfare and productivity. Commonly divided in infectious and noninfectious depending on their aetiology, infectious lesions include digital dermatitis, interdigital dermatitis, heel horn erosion, and foot rot, whereas the most common non-infectious lesions are sole ulcer, toe ulcer, sole haemorrhage, and white line disease. Infrared thermography (IRT) has been adopted in livestock studies for different analyses such as metabolic responses to thermal stress and the diagnosis of inflammatory processes. The aim of this study was to evaluate the potential usefulness of infrared thermography as a non-invasive tool to rapidly screen digital and interdigital dermatitis (DD and ID) in dairy cows. Forty-eight healthy cows and forty-eight cows affected by DD and ID on central and interdigital regions of the hind feet were enrolled. Feet were cleansed to reduce biases and artifacts and left to dry for five minutes to restore normal blood flow. Thermography images of the hind feet were then collected using a digital infrared camera. Foot temperature was measured in four regions: central area of the hind foot (R1), interdigital area of the hind foot (R2), lateral (R3) and medial (R4) claw in the hind foot. Higher temperature values were found in the central (R1) and interdigital area (R2) compared to lateral (R3) and medial (R4) areas in both healthy and diseased cows (P<0.001). Moreover, cows affected by DD and ID showed higher foot temperature values compared to healthy cows in the R1 and R2 regions (P<0.001). Results from the present study show that IRT could be a useful diagnostic tool for the detection of DD and ID in dairy cows. The obtained results suggest that IRT could contribute in defining the localization of areas of increased inflammation and could be useful for veterinary podologists, permitting to act directly on the lesion detected by thermography rather than on the whole foot.