Pretreatment effect of human chorionic gonadotropin and estradiol-17β on ovarian response, embryo production and endocrine profile in cattle superovulated with FSH-P*

Abstract

Pretreatment effect of hCG and estradiol- 17 β on superovulatory response by exogenous administration of FSH was studied in 15 adult cyclic crossbred cows randomly divided in 3 groups. Group I animals received 40 mg FSH-P in 6 doses of constant 3 days schedule from day II of cycle; 25mg of PGF2α was injected with last FSH injection. Group 2 animal received 500 IU hCG (im) on day 9 and 2mg estradiol (sc) on day 10 followed by superovulation on day II. Group 3 animals received 250 IU hCG in place of 500 IV hCG. Other treatments were similar to that of group 2 animals. Animals were inseminated at 0, 12 and 24 hr after onset of estrus. The ovarian response and embryo quality was recorded after nonsurgical collection on day 8. Blood plasma collected during the experiments was subjected to FSH, progesterone and estradiol estimation.  Ovulation rate did not differ significantly among the different treatment group 3. However, comparatively higher number of transferable embryos were recorded from the 250 IU hCG and estradiol pretreatment (4.75±0.94) in comparison to control (1.60± 1.12) or 500 IV hCG (2.00±1.37). Increased FSH, estradiol level at estrus and progesterone on day of flushing was positively correlated with transferable embryo. It may be concluded that pretreatment of low dose of hCG and estradiol prior to superovulatory treatment probably develops more follicles and ovulate synchronously, thus enhances transferable embryo production.