Follicle Wave and Natural Estrus Synchronization Superovulation in Holstein Cows.

The effects of two superovulation protocols were compared (synchronization of the follicle wave SFW and natural estrus NE) in embryos collected from Holstein cows. Twenty cows were chosen as donors, body condition of 2.75 -3.5; between 40 and 60 months, with normal cycles and no breeding problems. The cows were randomly assigned to SFW treatment (n=10), and the NE treatment (n=10). The SFW group was synchronized with intravaginal progester-one plus estradiol benzoate, on day 0, and increasing doses of FSH for 4 days, twice a day, from the 4th on. The im-plant was removed on the 6thday, and prostaglandin was applied. On the 8th day, insemination was made at 6 am and 6 pm. The NE group received increasing doses of FSH twice a day, during 4 days, from the 10th day. On the 12th day prostaglandin was administered, and insemination took place on the 14th day, at 6 am and 6 pm. The em-bryos were recovered from the two groups without surgery, 7 days after the first artificial insemination. The values of embryos for transference were 5.7 + 0.76 and 2.8 + 0.31 (P < 0.05) for SFW and NE, respectively