RESUMO
Infrared thermography (IRT) can measure a temperature change on the surface of objects, and is widely used as an inflammation or fever detection tool. The objective of this longitudinal study was to investigate the feasibility of detecting hoof lesion cattle using IRT under subtropical climate conditions. The experiment was conducted in two free-stall commercial dairy farms and 502 dairy cows participated between August 2020 and March 2022. Before hoof trimming, the portable IRT was used to measure the maximum temperature of each hoof from three shooting directions, including anterior (hoof coronary band), lateral (hoof lateral coronary band), and posterior (skin between heel and bulbs). In order to evaluate the effect of hoof lesions on the behavior of dairy cows, we also collected behavior data by automated accelerometers. The results indicated that the temperature of hooves with lesions was significantly higher than that of sound hooves in hot environments regardless of the shooting directions (P < 0.0001). In all of three shooting directions, the maximum temperature of feet with severe lesion was significantly higher than those of feet with mild lesion and sound feet (P < 0.05). Cows with lesion feet had lower daily activity and feeding time than sound cows before clinical diagnosis (P < 0.05). Furthermore, we used thresholds of both anterior hoof temperature at 32.05 °C and average daily activity at 410.5 (arbitrary unit/d) as a lame cow detecting tool. The agreement of this integrated tool reached 75% with clinical diagnosis, indicating that this integrated approach may be feasible for practice in dairy farm. In conclusion, IRT has the potential to be used as a hoof lesion detecting tool under subtropical climate conditions when using sound hoof temperature as reference points, and detection precision can be improved when IRT integrated with automated accelerometers as a lame cow detecting tool.
Infrared thermography (IRT) has been considered as one of the most effective tools for identification of hoof lesions in dairy cows. However, ambient temperature had been proven to affect the measurement of the IRT. The purpose of this current study is to investigate whether IRT could detect changes in hoof temperature on the feet with lesions under subtropical climate conditions. The results indicated that the maximum temperature of affected hoof was significantly higher than that of nonaffected hoof even in hot environments. The diagnostic accuracy of the IRT could be above 70%. When combining daily activity value collected by accelerometer of each cow with hoof temperature as a hoof lesion detected criterion, the accuracy of this integrated diagnostic tool could elevate to 75%. This suggests that IRT can be used as a hoof lesion detecting tool under subtropical climate conditions.