Reproductive Cows’ Response To Exogenous Hormone Treatments And Changes Of Endogenous FSH Concentration

Experiment 1 Effects of Exogenous Hormone of different dosages on Cow’s reproductive performanceIn order to study effects of the different dosages of PGF2α and Gn RH for ovary, uterine involution and The non-return rate on cows to improve the reproductive performance of cows. Selected 15 cows whose body condition score(BCS) are from 2.5 to 4(test group ?) and higher than 4(test group Π) respectively.They were randomly divided into 3 groups(A, B, C, n=5). Used program of estrus synchronization and accurate Timing of insemination of 3 different dosages of PGF2α and Gn RH, reading cervical mucus score and the rectum test score.Then analyzed the change of estrus rate and the non-return rate of cow to determine the optimum dosages of PGF2α and Gn RH. the results showed that :1. Low dosages hormone treatment cows of BCS=2.5-4, Cervical mucus score and the rectum test score showed a rising trend after 14 t h day and Cervical mucus score and the rectum test score were significantly increased to 4.05(P<0.05) and 3.45(P<0.05) in 35 t h day.2. High dosages hormone treatment cows of BCS>4, Cervical mucus score was significantly increased to 3.84(P<0.05) in 28 t h day and increased to 4.12(P>0.05) on 35 t h day. the rectum test score were significantly increased to 3.54(P<0.05).3. Effect of estrus synchronization is better and The non-return rate is higher when PGF2α =0.6mg and Gn RH =60μg for BCS is 2.5-4, effect of estrus synchronization is better when PGF2α =0.8mg and Gn RH =80μg for BCS >4.Experime nt 2 Effects of different Exogenous Hormone treatments on ovulatory cows and the change of Endogenous FSH concentrationIn order to perfect technology of estrus synchronization and accurate Timing of insemination. Discussing effects of combine use PGF2α and Gn RH for ovary, uterine involution and the non-return rate on cow. Selected 40 cows of postpartum 90 daysor more, not estrus, and infertility after more than 2 times artificial insemination.They were randomly divided into test group ? and Π(n=20). In addition. Used program of estrus synchronization and accurate Timing of insemination for test group ? and Π, reading cervical mucus score and the rectum test score. We analyzed the change of the concentration of FSH in blood to compare the rate of estrus synchronization and the non-return rate of different program. The results showed that:1.Cervical mucus score and the rectum test score were respectively increased by 0.55(P<0.05), 0.45(P<0.05) before and after the test group ? and respectively increased by 0.30(P<0.05), 0.45(P<0.05) before and after the test group Π; cycle estrus rate is 80% and 90% respectively.2. During 0-32 days, endogenous FSH concentration showed increasing trend test ?, on the 33 t h day appeared a peaks value is 21.05 ng/m L, decreased to 14.32 ng/m L on the 34 t h day, finish ovulatory on the 33 day, at this time The non-return rate can reach to 65% by artificial insemination. During 0-26 days, endogenous FSH concentration showed increasing trend test Π, on the 27 t h day appeared a peaks value is 20.68 ng/m L, decreased to 19.32 ng/m L on the 28 t h day, finish ovulatory on the 27 t h, at this time the non-return rate can reach to 65% by artificial insemination.3. The first cycle estrus rate are 65% and 70% test(?、Π) respectively.4. The two programs of estrus synchronization and accurate timing of insemination could promote the ovary and uterine involution, start the normal reproduction function, to achieve the effect of estrus synchronization, improve the reproductive rate of dairy cow.