The multicellular structures are connected through junctional complexes, thus forming the primary barrier function (Matter and Balda, 2003). In addition, rumen epithelial cells interact with lymphocytes and dendritic cells in lamina propria to maintain immune homeostasis (Trevisi et al., 2014). In goats, a high-grain diet (65% grain) could cause massive disruption of ruminal epithelial tight junctions when compared to the control diet (0% grain) (Liu et al., 2013). Despite this, a systematic characterization about how rumen mucosal innate immune function developed during early life is still not well-defined.