PSIII-14 Infrared thermography as a tool to detect inflammation in feedlot lambs with footrot

Abstract

Abstract Infrared thermography (IRT) has been used as a non-invasive tool to detect inflammatory processes associated with disease in livestock. The aim of this study was to evaluate IRT as a tool to compare healthy and footrot (FR) affected hooves in feedlot lambs with varying degrees of lameness over two seasons. A total of 106 lame lambs with footrot from a feedlot in Alberta were individually categorized according to a 3-point locomotion scale [1 = mild (n = 7), 2 = moderate (n = 46) and 3 = severe lameness (n = 53)] during the summer (n = 39) and fall (n = 68) of 2018. All lambs were physically examined once by two experienced observers to determine if the lamb had footrot. IRT images of the interdigital space were used to obtain the maximum hoof temperature (MHT) of both FR affected as well as healthy (CT) hooves within the same animal. Generalized linear mixed models (SAS PROC GLIMMIX) were performed separately for each season and diagnosis and included locomotion score as a fixed effect and ambient temperature as a co-variate. Predicted means were compared using the limits at 95% of confidence. Overall, greater MHT (P < 0.05) were observed for FR affected compared to unaffected hooves for lambs categorized as moderately and severely lame, within each season. However, no differences (P > 0.05) in MHT were observed for lambs categorized as mildly lame, likely due to the small number of lambs having a locomotion score of 1. Under the conditions of this study, thermal images can be effectively used as a tool to distinguish footrot affected hooves in feedlot lambs with moderate and severe lameness. Further studies should be conducted with more lambs with a locomotion score of 1 to assess the relationship between mild lameness, IRT, and footrot diagnosis.