Studies On Relationships Between Reproductive Hormones Of Ruminants And Dietary Energy

Twenty-four primiparous Chinese Holstein cows that are in early lactation period, twenty-one local goats and sheep, respectively, nine Xiaowei sheep which were in prepuberty were selected to study relashionships between reproductive hormones and energy balance. The experiment lasted sixty to sixty-five days. Study indicate that DMI and production performance are major factors which are affect energy status of dairy cows, milk yield was related negatively to energy balance, r= -0.5908**, weeks of post-partum and DMI were related positively to energy balance, correlation coefficients were 0.5722 and 0.0935**, respectively. PRL was related highly, significantly and negatively to energy balance, r= -0.9618**, due to PRL increased, milk yield was increased, make energy status become worse. The regression equation is: Y= -0.4269X+9.2283 (n=18,R2=0.9251**) When PRL is great than 9.23,dairy cattle are in negative energy balance . Insulin and GH of ruminant were related negatively and weakly to energy balance in lower energy status, when energy reached to certain status, they were related positively and weakly to energy balance. Compare with insulin, reaction of GH to energy status occurred late, this indicate insulin regulate GH. The regression equations between them and energy balance are: Insulin of dairy cows Y=0.0007X3+0.0260X2-0.2731X+5.2976 (n=18,R2=0.7839**) GH of dairy cows Y=0.0002X3-0.0009X2-0.0382X+0.6116 (n=18,R2=0.7354**) Insulin of indigenous sheep Y= -881.6949X3+4003.7033X2-6001.1057X+2979.7455 (n=14, R2=0.7156**) GH of indigenous goat Y= -40.1693X3+193.1017X2-302.4795X+155.8794 (n=14, R2=0.7755**) The yield of FFA daily were related negatively to energy balance of milking cows, r= -0.1917**. The regression equation was: Y= -1.1223X+86.5066 (n=216, R2=0.0367**, P〈0.0047) Serum concentration of estradiol, estriol, LH and progesterone of dairy cows in duration of estrus are higher than in luteal phase when corpus luteum reached its maximum volume. Duration of estrus is characteristics by estrogens Correlation coefficients among serum estradiol concentrations in duration of estrus and energy balance of the first week previously, 1-3 previously, weeks 4-6 previously, the seventh week previously are –0.2064, -0.2541, 0.7712 and 0.9675, respectively, the correlation coefficients increased gradually. Regression equation between estradiol and energy balance of previous seventh week is: Y=2.1347e0.0191x (n=5, R2=0.9470) Correlation coefficients among Serum estriol concentrations in duration of estrus and energy balance of the first week previously, weeks 1-3 previously, weeks 4-6 previously, the seventh week previously are –0.2790, -0.1716, -0.3703 and 0.4933, respectively, the tendency of variation is similar to estradiol, but the correlation coefficients are lower than estradiol. The regression equation between estradiol and energy balance of the seventh week previously is: Y=0.2595e0.0574X (n=5, R2 =0.4998)...