Infrared thermal imaging of udder skin surface temperature variations to monitor udder health status in Bos indicus (Deoni) cows

The study was conducted to evaluate the potential of infrared thermography (IRT) technique for the early detection of subclinical mastitis in indigenous cows. A total of fifty-six quarters of lactating Bos indicus (Deoni) cows (n = 14) were monitored for ocular surface temperature (OST) and udder skin surface temperature (USST) prior to morning and evening milking using FLIR i5 (forward-looking infrared) camera continuously for 28 days. Milk samples were collected from each quarter and screened for mastitis using Somatic Cell Count (SCC), Electrical Conductivity (EC) and California Mastitis Test (CMT). Thermographic images were analyzed by using FLIR Quick Report 1.2. Data on OST and USST were compiled and analyzed statistically using SPSS 16.0. The mean (±SD) OST (i.e. body temperature) of an individual cow during the study period was 36.10 ± 0.08 °C. The mean (±SD) OST (36.10 ± 0.08 °C) and USST (36.19 ± 0.06 °C) of un-affected cows did not differ significantly, however, the mean (±SD) USST of the subclinical mastitis-affected quarter was 37.61 ± 0.29 °C which was 1.51 °C higher than the body temperature (P < 0.001). The increase in USST of subclinical mastitis quarters showed a positive linear relation with the SCC and EC with R2 > 0.95. The maximum udder skin surface temperature of 37.90 was taken and used for the ROC analysis. The ROC curve analysis revealed a higher sensitivity and specificity for difference between OST and USST and their potential for detection of subclinical mastitis with a cut-off value >0.58 °C. Infrared thermal imaging technique could be used as a potential noninvasive, cow-side diagnostic method for screening and detection of subclinical mastitis.