Therefore, SI may inhibit the expression of FAK by inhibiting the secretion of ITG-β5 and OPN, so as to reduce the ability of S. agalactiae to invade the bovine mammary epithelial cells and achieve the protective effect of soybean isoflavone on the mastitis induced by Streptococcus agalactiae. The gene discussed is ITGB5; the disease is mastitis.