TLR4 and mastitis: Moreover, we showed that low-grade LPS exposure induced mastitis through reducing host ALP activity by the TLR4-neuraminidase (Neu)-ALP pathway, which further deteriorated E. coli-induced mastitis, as evidenced by supplementation with calf intestine alkaline phosphatase (cIAP) or the Neu inhibitor zanamivir, thus alleviating mastitis caused by low-grade LPS or E. coli.