The study showed that exposure of the pregnant sow to the probiotic microbes contained in EM Bokashi® significantly affects the immunological quality of the colostrum and milk and caused an increase in the percentage of the subpopulations of B cells with CD19+, CD21+, and CD5+CD19+ expression in the colostrum and milk, which demonstrates an increase in the protective potential of colostrum and indicates stimulation of humoral immune mechanisms that protect the sow and the piglets against infections. Here, CD19 is linked to infection.