For the study on the influence of daidzein on cows, 14 Holstein dairy cows with similar milk productivity in late lactation were assigned randomly to treatment and control groups. Cows in treatment group were fed with 10mg/kg daidzein for 30 days. Results showed that daidzein could lessen the declining tendency of milk yield in late lactation and increased the milk yield to some extents; Contrasted with control group, lactoprotein was increased while butterfat percentage decreased. The levels of GH (P<0.05) and PRL (P<0.01) in plasma on the 30th day were evidently increased; the levels of E2, T3 and T4 prone to rose. It could be concluded that daidzein could indirectly affect milk yield and components of milk by regulating the levels of intrinsic hormones.
