It should be noted that a significant difference in concentration of IL-6 in the milk compared to the control group was recorded for both cows with clinical and subclinical mastitis (487.09 pg/mL vs. 26.6 pg/mL in CM, p < 0.001; and 165.31 pg/mL vs. 26.6 pg/mL, p < 0.001). Here, IL6 is linked to mastitis.