WW domain-containing transcription regulator 1 (WWTR1) is one of the primary effectors in Hippo pathway, which plays essential roles cell differentiation into trophectoderm (TE) and inner mass lineages at blastocyst stage. However, little known about WWTR1 preimplantation development. The present study aimed to explore significance expression development using an mRNA knockdown (KD) system bovi...