The potential of infrared thermography for the detection of dairy cattle lameness

Introduction
Lameness studies, specifically on the pathogenesis of claw horn disruption have demonstrated that the early detection and treatment of lame cows is vital to prevent chronic irreversible claw damage. Several techniques exist to detect lameness in dairy cows these include locomotion scoring (LS), automatic gait analysis, and infrared thermography (IRT). These techniques vary in their on-farm feasibility, particularly for pasture-based systems. Several studies have suggested that increased foot temperature, as detected using infrared thermography technique is a potentially useful technique for identifying lame cows. However, the studies published so far have been undertaken in housed cows, not cows kept permanently at pasture. The present study aimed to evaluate the use of IRT as a tool for detecting lameness in a pasture-based dairy herd. 

Materials and Methods
The plantar aspect of the hind limbs of 166 cows was imaged using a T650sc Forward Looking Infrared camera (FLIR systems Inc. USA) during milking in a rotary parlour. This was followed by whole herd locomotion scoring as the cows exited the milking parlour (Dairy-NZ 0-3 scale). The foot was divided into seven zones, i.e., coronary band, above the coronary band, below the accessory claw (dewclaw), and interdigital space for the analysis. The effect of zone and foot on mean temperature was then analysed as well as the association between locomotion score and foot skin temperature. 

Results
Of the 166 cows imaged, 33 (19.9%) had LS 0, 95 (57.2%) had LS 1 and 38 (22.9%) had LS ≥2 there was a significant effect of zone and foot (but no interaction) on temperature (P < 0.001), Figure 1. However, although there was an association between mean temperatures and locomotion score with mean temperature in cattle with locomotion score 0 having lower foot skin temperatures than cows with score 1 or ≥2 (P = 0.005 and 0.022, respectively), there was no significant difference between the mean temperatures for cows with score 1 and ≥2, Figure 2. 

Conclusions
Further analysis is required to identify better whether there is a relationship between locomotion score and foot skin temperature in pasture-based dairy cows that would be useful in determining lameness without locomotion scoring.