The effect of different levels of teat-end hyperkeratosis on mammary infrared thermograph and mastitis in dairy cows

The object of this study was to assay different levels of teat hyperkeratosis and to determine the connections between teat thermographic characteristics, somatic cells count (SCC) and mastitis in dairy cows. A total of 920 teats of 230 Lithuanian Black and White cows were evaluated to assess teat-end conditions and the thermographic characteristics were determined before evening milking. Teats of the animals were grouped into four different classes of hyperkeratosis. Additionally, quarters of udder were divided into three different classes based on the California mastitis test (CMT) and clinical signs: group 1 (healthy), group 2 (subclinical mastitis), and group 3 (clinical mastitis). The 44.3% of the teats were given a score of N (No ring), 41.1% of the teats were scored S (smooth ring), 11.8% of teats were given a score R (rough ring) and 2.9% of teats were given a score VR (very rough skin). The N and S groups had more healthy udder quarters than R and VR groups (P<0.001). Analysis of thermographic images at the teat sinuses showed that group 1 had lower teat temperature (0.93-1.32 degrees C) than group 2 and group 3 (P<0.01). There was a significant positive correlation between milk SCC and temperature of the teats evaluated by hyperkeratosis scores N, S, and R. The results of the present study clearly showed that there was a significant connection between different levels of hyperkeratosis and teat temperature in all groups, indicating a greater risk to mastitis.