In the present study, no significant difference in the expression of TNF-α or IL-8 was observed when animals of the two breeds with mastitis were compared; however, expression of the two genes seemed to be higher in BW Holstein cows (Table 2), a fact that disagrees with the results obtained by others since in the present study all BW Holstein cows with mastitis were infected with Staphylococcus spp. Here, TNF is linked to mastitis.