Effects of Prostaglandin,N-methyl-D-aspartate and Letrozole on Ewes Plasma Levels of Reproductive Hormones were Evaluated on the Basis of Medroxyprogesterone Acetate Supplementation

This study was aimed to investigate the effects of the different compatibility of medroxyprogesterone acetate (MPA) with prostaglandin(PG), N-methyl-D-aspartate (NMDA) and letrozole (LE) on plasma related hormones levels of reproductive ewes. Thirty-nine and 3-year-old multiparity Suffolk ewes with average weight (75.51+11.55)kg were selected,and assigned into 3 groups,test group Ⅰ:Basis diet+34 mg/d MPA+1 mL/ewe PG, test group Ⅱ:Basis diet+34 mg/d MPA+600 mg/d NMDA, test group Ⅲ:Basis diet+34 mg/d MPA+ 14 mg/d LE, respectively, the trial period lasted for 18 days. The results showed as follows:On the basis of supplemental feeding MPA with PG treated,the levels of FSH in plasma of ewes were extremely significantly increased (P<0.01); Treated with NMDA, the levels of E₂, MLT,FSH and LH in plasma of ewes were extremely significantly increased (P<0.01), respectively;Treated with LE, the levels of MLT,LH and T in plasma of ewes were extremely significantly increased (P<0.01), respectively. This study suggested that MPA+NMDA and MPA+LE could be used as medicines for regulate and control oestrus of ewes, and the effect of MPA+NMDA was the best.