Effect Of Daidzein On The Lactation And The Levels Of Some Pertinent Hormones Of Cows

Effects of daidzein on the lactation and the levels of some pertinent hormones of dairy cows were studied in the experiments.In experiment I , four 6-year-old Chinese Holstein cows in their 7th month of the 3rd lactation were studied. Self-control method was used and the test was divided into control and treatment periods. Daidzein was added in the concentrate by lOppm during the treatment period, while during the control period daidzein was not added. The results showed that feeding daidzein can lessen the decline tendency of milk yield in later lactation phase and improve the milk yield to some extent; the concentration of lactoprotein was significantly increased(P<0.01) while the milkfat percentage was not evidently affected by daidzein administration. The T4 level of the serum and of the milk were all markedly raised (PO.05), and the levels of GH, PRL, E2 and TSH of the serum as well as of the milk had increasing tendencies while T3 showed a tendency of decline; compared with the control, the levels of ?, GH, PRL and TSH of the serum in the treatment were respectively increased by 36.46%, 33.75%, 13.13% and 6.65%, and those of the milk were respectively raised by 7.43%, 6.79%, 8.71% and 3.76%, while the T3 levels of the serum and of the milk were dropped by 25.67% and 7.79% respectively, but all the differences were not evident.In experiment II, 14 Holstein dairy cows similar in parturition37numbers and lactation period were divided into treatment and control groups. The test lasted 30 days, during which the treatment concentrate was added with 10ppm daidzein while there was not daidzein addition in the control concentrate. The results showed that feeding daidzein can lessen the decline tendency of milk yield in later lactation phase and the milk yield was improved to some degree; the content of lactoprotein was increased while the milkfat percentage was dropped, but all the differences were not significant; the GH content of the milk on the 15d was evidently increased (P<0.05); the GH (P<0.05) and PRL (P<0.01) levels of the plasma on the 30d were markedly raised; in addition, all the levels of E2, T3 and T4 of the plasma as well as of the milk had increasing tendencies. On the 30d , compared with the control, the levels of e2, T3 and T4 of the plasma were increased by 5.15%,8.38% and 7.14% respectively and those of the milk were increased by 4.52%,22.86% and 20.77% separately.The results indicated that daidzein can indirectly increase milk yield and lactoprotein content of the treated dairy cows.