Fate of the dominant follicle, embryonal survival, and pregnancy rates in dairy cattle treated with prostaglandin F2 alpha and progestins in the absence or presence of a functional corpus luteum.

摘要: Our objective was to examine the role of progestin type on serum concentrations progesterone (p4) and estradiol-17 beta (E2), ovarian follicular dynamics, fertility in cattle presence or absence a corpus luteum (CL) an estrus synchronization scheme using PGF2 alpha. In Exp. 1, 325 cows heifers were given one injection alpha (d 0) then assigned randomly within parity five treatments: receive second 14 d later (control); norgestomet (NORG) for 7 beginning 8, with either 1 (NORG + no CL) 6 after insertion; P4-releasing intravaginal device (PRID) lieu at comparable times. Presence CL based P4 14. Pregnancy rates insemination greater (P < .01) luteal treatments than nonluteal treatments. Embryonal survival between two stages pregnancy 87.6%. 2, structures 50 examined daily ultrasonography same Diameter ovulatory follicle .05) PRID control (PRID NORG CL). Replacement dominant during treatment altered by (luteal status) stage estrous cycle. Fertility not enhanced exogenous progestins when present. CL, (P4 less doses used) reduced increasing E2 diameter decreasing turnover follicles.