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1. 1
Estrus synchronization and
ovulation

2. ESTROUSCYCLE
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• GnRH Hypothalamus
↙ ↓
LH AnteriorPituitary
• FSH
• Estrogen (E2) Follicularcells
• Progesterone(P4) CorpusLuteum
• PGF2α UterineEndometrium

3. ESTROUSCYCLE
3
• G
nR
HstimulatestheAnteriorP
ituitary to releaseF
SH
• FSH actson the ovaryto beginfollicular development
• Folliclesgrowsuntilmatureandestrogen inhibitsF
S
H
• ThiscausestheAnteriorPituitaryto releaseLH
• LHactsonthefollicleburstingtheblister
Ovulation.
• Spot on the ovary becomes the CL
• – CL produces progesterone
• On day 14 if the uterus does not detect an embryo then it releases
PGF2α
• PGF2α destroys the CL (Luteolysis) and the cycle begins again

4. COMMERCIALAVAILABLE
HORMONES
4
GnRH(Buserelin acetate)  ReceptalVet,
Gynarich (each ml contains4mcg)
2.5 ml (10mcg)

5. PROSTAGLANDINS (PGF2Α)
5
Synthetic (Cloprostenolsodium)=Pragma,
Cyclix,Vetmate, Clostenol, Estrumateetc.
 2 ml vials (500mcg)
Natural =Lutalyse (Dinoprosttromethamine)
 5 ml vials(each ml contains25 mg)

6. ESTROGENS
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• ProgynoneDepot (Estradiolvelerate,1 ml
Ampoules, 10mg)
• Pregheat (Estradiol benzoate2 ml vials, 1 mg))

7. PROGESTERONE
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• CIDR=ControlledInternal DrugRelease
• PRID=ProgesteroneReleasingIntravaginal
Device.
• silicone-coated nylon coreimpregnated
with progesterone

8. ESTRUS SYNCHRONIZATION
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Administrationof exogenoushormones
↓
Manipulationof femalesestrouscycle
↓
Estrus(heat) athe sametime
↓
AI/Breeding at sametime.
• Many estroussynchronizationprotocolshave been
developed that useacombination of different
drugs.

9. WHY SYNCHRONIZE
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• Many estrus synchronization protocols can
induce 75 to 90% of the cycling animals to
display estrus withina5 dayperiod.
• Many protocols can induce a fertile heat as
much as50%of theanestrous cows.

10. METHODS OF
SYNCHRONIZATION
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Twobasicmethods of estrussynchronization-
A. Extendingthe lutealphase
B. Shorteningthe lutealphase

11. A. EXTENDING THE LUTEAL
PHASE
 Longterm administration of progestogen withdrawal
of progestogen  C
Lregression Estrus.
 Negative feedback on LHsecretion afterC
Lregression.
 Onprogestogenwithdrawal,folliculargrowth, estrusand
ovulationoccurswithin 2to 8 days.
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12. 12
• Severalmethods of administration of
progestogen are commerciallyavailable.
• E.g.Orally active progestogens(Altrenogest),
Pessaries,Earimplants and Intravaginal
devices(CIDR,PRID).
• CIDR=ControlledInternal DrugRelease
• PRID=ProgesteroneReleasingIntravaginal
Device.

13. B.SHORTENING THE LUTEAL
PHASE
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• ByUsingPGF2α
1. Oneshotmethod: Inject PGF2α,heatdetect
and breed within 7days.

14. 2. TWOSHOTMETHOD:
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a. Option 1:
– Inject PGF2α,heat detect and breed within 7 days,
– inject again on day 11-14, heat detect and breed
within 7 days
b. Option 2: inject PGF2α, then again on day 11-14,
heat detect and breed

15. CIDR
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• CIDRs(Controlled Internal Drug Release)are
an intravaginal progesteroneinsert.
– Theprogesterone is released at acontrolled rate
into the bloodstream after insertion.

16. CIDR
• Insert CIDRand inject with GnRHon day0
• Day6 inject with PGF2α
• RemoveCIDRon day 7 and beginheat
detection
• Shouldbreed 48 hrs after removal of CIDR
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CIDR+
GnRH
PG
Remo
ve
CIDR
Day7
AI
Day0 Day6 Day9

17. HOW CIDRWORKS
 CIDRsare coated with progesterone.
 Progesteronewill preventthe animalfrom going into
heat (ActasArtificial CL).
 CIDRremoved  progesterone leveldecrease
  Estrusandovulation.
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18. OVSYNCHPROTOCOL
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19. OVSYNCHPROTOCOL..
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• Ovsynchoccurs in threestages
Day0 : GnRHinjection to create anew follicle,
Ovulate dominant follicles and leutinize follicles
Day7 : PGF2αinjection to end the current estrus
cycle and regress the corpus luteum
Day9 : SecondGnRHinjection to causethe new
follicle to ovulate and release the egg
• Allcowswill ovulate 24-32 hours after thesecond
GnRHinjection
Day10 :AI

20. MODIFIED OVSYNCH(COSYNCH
PROTOCOL)
• AI or breeding simultaneouslywith second
injection of GnRH.
• Reducestime spend on heatdetection.
GnRH PG
GnRH
+AI
Day0 Day7 Day9
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21. HEAT SYNCHPROTOCOL
• Useslessexpensive estradiol cypionate(ECP)
in place of 2nd GnRHinjection ofOvsynch.
• AI 48 hrs. after estradiolinjection or 72 hrs of
PGF2αinjection.
GnRH PG ECP
Day0 Day7 Day9 Heat/AI
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22. SELECT SYNCHPROTOCOL
• Heat detection 24-48 hrs. beforePGinjection.
• ExcludePGfor animalsin heat on day6 or 7.
• Heat detection andAI at 48 to 60 hrs. after
PG.
• GnRHand timed AI of non respondersat 72
hrs after PG
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GnRH PG
GnRH
+AI
Day0 Day7 Day10
Heat/AI Heat/AI

23. HYBRID SYNCHPROTOCOL
• Heat detection andAI after PG.
• GnRHandAI of non responders at 54-80 hrs
after PG
GnRH PG
GnRH
+AI
Day10
25
Day0 Day7 Day8-9
Heat/AI

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