![iv) Double-Ovsynch
• Double Ovsynch results in a higher pregnancy rate than the
Presynch-Ovsynch protocol in primiparous (65% versus
45%) but not multiparous [38% versus 40%] cows.
GnRH PGF2α GnRH 1st GnRH PGF2α 2nd GnRH
3 days later 7 days later
Day 0 Day 7 10 17 24 27 28
AI at 8-18 hours post 2nd GnRH
• The improved pregnancy rate was probably due to the increased
probability of a dominant follicle that would ovulate following
the third GnRH, and the elevated circulating progesterone
concentrations prior to the administration of PGF.
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Estrous synchronization in farm animals
- 1. ASSISTED REPRODUCTIVE TECHNOLOGIES Synchronization of estrus and Ovulation Dr. Farooz Ahmad Lone Assistant Professor (Ph.D Gold Medalist)
- 2. Assisted reproductive technologies (ART) can be defined as techniques that manipulate reproductive-related events and/or structures to achieve pregnancy with the final goal of producing healthy offspring. • Artificial insemination (AI) • Estrous Synchronization • Superovulation and embryo transfer (MOET) • In vitro handling of oocytes and production of embryos • Embryo splitting • Reproductive cloning (SCNT) • Embryo and semen sexing • Transgenesis • Genomics for marker-assisted selection • Gene editing (CRISPR cas technology)
- 3. Synchronization of estrus and Ovulation • Manipulation of estrous cycle or induction of estrus to bring a large percentage of a group females into estrus at a short predetermined time. • Estrus synchronization minimizes problems associated with estrus detection, such as labor costs and estrus detection errors. • Estrus synchronization allows the more efficient use of artificial insemination with the use of elite sires having superior genetic makeup and embryo transfer procedures.
- 4. Basic approach “Control the timing the onset of estrus by controlling the length of the estrous cycle” How to control • Shortening of luteal phase • Extending the luteal phase • Use of GnRH to cause ovulation of dominant follicle
- 5. Shortening of luteal phase • To induce death of CL before actual time of luteolysis Prostaglandins • Natural • Synthetic analogues Dose and route? • Extending the luteal phase To mimic the action of CL • Natural progesterone (Sponges) • Synthetic (MGA, FGA, MAP)….30, 40, 45 mg giving natural progesterone
- 6. • 0.3g of natural P4 in DICO (Dispositivo intravaginal Caprino ovino) and CIDR-G • Eazibreed (CIDR)…….T-shaped device impregnated with 1.38 gm progesterone • TRIU-B 3 medicated rings (green colour) containing Progesterone 186 mg each and one additional ring (pink colour) with Progesterone IP 400 mg.
- 7. GnRH analogues to cause ovulation of dominant follicle • Buserelin acetate (10-20µg) Preparations…….. Methods of estrous synchronization A) Prostaglandin treatment • Cyclic females • During breeding season in seasonal breeders (Sheep and goat)
- 8. a) Single shot PGF protocol • Estrus within 48-72 hours PGF2α Detect heat and breed Day 0 Day 7 Day 21 b) Two shot PGF protocol PGF2α PGF2α or PGF2α Detect heat & breed 5-7 days Day 0 Day 11 Day 14 Day 21 • Most common, breed those detected in heat post 1st PGF. • Not in heat are injected 2nd PGF at 11-14 days apart • In sheep 9 days apart. .
- 9. B) Progesterone treatment a) Melengesterol feeding (MGA) Option-1: The MGA system • Feed animals MGA @ 0.5 mg/head/day for 14 days • After removal of MGA, most animals will show heat • Skip this heat and breed on next natural heat Option-2a: The MGA-PGF system Stop MGA PGF2α 0.5 mg MGA/head/day do not breed detect heat & breed Day 0 Day 14 Day 31-33 Option-2b: Stop MGA & inject PGF2α 2nd PGF2α 0.5 mg MGA/head/day 15 days later detect heat & breed Day 0 Day 14 Day 29 .
- 10. b) Synchro Mate-B (CEVA laboratories) (3mg Norgestomet-2 ml + 5 mg estradiol valerate) (removal of implant) 6 mg norgestomet ear implant detect heat & breed Day 0 Day 9 Crestar: 3 mg norgestomet ear implant as against 6 mg (MSD) • Norgestomet inhibits LH secretion which inhibits the function of the corpus luteum. • The estradiol valerate stimulates PGF 2 alpha release which causes a breakdown of the corpus luteum. .
- 11. C) CIDR (Eazi breed® Pfizer) 1.9 g progesterone Removal CIDR detect heat & breed Day 0 Day 7 • It maintains high concentration of P4 in blood D) CIDR+PGF system PGF2α Removal of CIDR CIDR detect heat & breed Day 0 Day 6 7 .
- 12. C) GnRH based synchronization system • Includes GnRH and PGF • Synchronization and fertility is good • Applicable in post partum anoestrus females • GnRH causes ovulation of dominant follicle and initiates new follicular wave just 2.5 days after treatment. a) GnRH-PGF system (Select Synch) GnRH PGF2α Day 0 5 7 10 Day 12 detect heat and breed • GnRH and Timed AI of non-responders on day 10 or 72 hours after PGF…………….Hybrid Synch .
- 13. b) GnRH-PGF-GnRH system • This system includes 2nd GnRH injection between 48-72 hours after PGF injection with timed AI. i) Ovsynch protocol (FTAI) AI at 8-18 hours post 2nd GnRH GnRH PGF2α GnRH Day 0 Day 7 9 10 • Tighter synchronization • Most females respond to this system • Estrus in non-cycling females at 30 days postpartum .
- 14. ii) Cosynch • Similar to Ovsynch except AI is done simultaneously with 2nd GnRH injection. GnRH PGF2α GnRH + AI Day 0 Day 7 9 • Ovsynch requires 4 trips through the working crate but Co-synch requires only 3. • Ovsynch synchronizes ovulation with AI while as Co-synch does not. .
- 15. iii) Presynch-Ovsynch • Presynchronization with PGF is used to ensure that all cows are at the most appropriate stage of the estrous cycle at the time of the first GnRH treatment. • Pregnancy rate following TAI is higher in cows treated with the “Presynch-Ovsynch” than in those treated with Ovsynch alone (49% versus 37%). PGF2α PGF2α GnRH PGF2α GnRH AI 12 days later 7 days later 48 hrs 8-18 hrs Day 0 Day 14 26 33 35 36 Presynchronization Ovsynch .
- 16. iv) Double-Ovsynch • Double Ovsynch results in a higher pregnancy rate than the Presynch-Ovsynch protocol in primiparous (65% versus 45%) but not multiparous [38% versus 40%] cows. GnRH PGF2α GnRH 1st GnRH PGF2α 2nd GnRH 3 days later 7 days later Day 0 Day 7 10 17 24 27 28 AI at 8-18 hours post 2nd GnRH • The improved pregnancy rate was probably due to the increased probability of a dominant follicle that would ovulate following the third GnRH, and the elevated circulating progesterone concentrations prior to the administration of PGF. .
- 17. D) Progesterone-GnRH-PGF system a) MGA-GnRH-PG protocol withdraw MGA GnRH PGF2α MGA 10 days later 7 days later detect heat & breed Day 0 Day 14 24 31 b) CIDR + GnRH GnRH PGF2α GnRH CIDR Either Cosynch or Ovsynch Day 0 Day 7 9 • Most common • CIDR prevents early heat that is inherent to GnRH based system .