Hormonal Profiles Associated with Treatment of Cystic Ovaries with GnRH and PGF2αwith and Without CIDR in Dairy Cows

Abstract

This study aimed to investigate ovarian and endocrine responses associated with treatment of cystic ovaries with GnRH, PGF2α, and +/-Progesterone-CIDR placement; and to determine pregnancy establishment following synchronization and timed artificial insemination in cows suffering from cystic ovaries. Ovarian cysts were typed rectally and ultrasonographically into follicular, luteinized and persistent types. Two schedules of treatment were designed, in Schedule-A, 15 cows with follicular (n=7), luteinized (n=3) and persistent (n=5) cysts were used. The cows received 2 injections of 100 ug GnRH (9 days interval) with 25 mg PGF2α administered 7 days after 1st GnRH dose. In Schedule-B, 14 cows with follicular (n=6), luteinized (n=3) and persistent (n=5) cysts were used. The cows administered GnRH and CIDR concurrently, then 25 mg PGF2α 7 days later. The CIDR was removed 2 days after PGF2α. Cows were inseminated 16 hours after 2nd GnRH dose. Blood samples were collected to assay progesterone and estradiol levels. In schedule-A, 57.1%, 33.3% and 40% of follicular, luteinized and persistent cysts were ovulated after 1st GnRH injection, while a total of 100%, 66.7% and 100% were ovulated after 2nd GnRH dose. The cows with follicular cysts appeared the highest rate of pregnancy (57.1%) followed by the luteinized and persistent cysts (33.3% and 40%). Of a total 15 cystic-treated cows, 7 were confirmed pregnant (46.7%). The concentration of progesterone was significantly (P<0.05) higher at 1st GnRH injection, then decreased after PGF2α injection and then increased again at 7 day after insemination. In schedule-B, after 1 GnRH dose, 66.7% of follicular, 0% of luteinized cysts and 80% of persistent were ovulated; with a 57.1% total ovulation rate. Following CIDR removal, 85.7% (12/14) cows ovulated the recruited follicles and developed a corpus luteum. Of a total 14 cystic-treated cows, 8 were confirmed pregnant (57.1%). Plasma estradiol declined following intra vaginal placement of CIDR, but markedly increased one day after removal. Progesterone decreased after CIDR removal, but increased again at presence of palpable corpus luteum. The developed corpus luteum and pregnancy rate were higher in schedule-B (+CIDR) than in schedule-A (-CIDR). In conclusion, treatment of cows with cystic ovaries with GnRH followed by PGF2α 7 days later resulted in recruitment of new healthy follicles, synchronization of ovulation and a marked pregnancy rate (with than without CIDR)

Keywords

• Cystic, Ovaries, Estrus, follicles, Pregnancy, Synchronization