In contrast, our earlier study on mastitis in cows with subclinical coagulase-negative staphylococcal mastitis was not consistent with the results of Hagiwara et al. [26] study because it showed significantly higher concentrations of IL-6 both in milk (20 times) and in serum (2.5 times) compared to healthy cows [31]. This evidence concerns the gene IL6 and mastitis.