Fig. 5

Anti-S. aureus-specific IgA antibodies in milk (OD values) following quarters’ infusion with S. aureus BM1006. OD values of S. aureus-specific IgA antibodies in milk following nasal immunization with FKSA or no immunization in the early stage of lactation. a Composite milk (three cows, n = 3). b Two quarters infused with S. aureus BM1006 in the gland cistern (six quarters, n = 6). c Two quarters mock-infused with PBS (six quarters, n = 6). Each data point represents the OD value for one sample, and the bar represents the mean. Black circles correspond to nasal immunization samples, white circles to non-immunization controls. *Significant difference between the mean on day 0 and day 7 after infusion in the same group (P < 0.05)