TLR4 and mastitis: The involvement of TLR signaling (particularly TLR2 and TLR4) in the host response to mastitis is well-documented (Buitenhuis et al. 2011; Ma et al. 2011; Mitterhuemer et al. 2010; Porcherie et al. 2012; Whelehan et al. 2011); however, less is known about the involvement of the NLR and RIG-I pathways (Moyes et al. 2009).