CXCL8 and mastitis: 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.