1. Estrous Synchronization (Ovulation Induction) and Ovsynch
John Parrish
Updated: 4/20/2017

2. Learning Objective
To understand how estrus synchronization and Ovsynch work along with how to use it successfully.
Updated: 4/20/2017

3. Estrus synchronization:
Why?
1. Group females for parturition:
a. Labor, Calving period
b. More uniform weaning weights.
2. Reduce time required for estrus detection.
3. Eliminate estrus detection with timed insemination:
Reduce calving season
Fertility may be higher in combination with estrus detection.
Updated: 4/20/2017

4. Cattle: Half-life in blood Prostaglandins: PGF2a
Lutalyse - Natural compound 25 mg dose I.M.
Estrumate - Analogue 500 mg dose I.M.
Bovilene - Analogue 1 mg dose s.q.
2-3 min
3-4 hrs
18-24 hrs
Updated: 4/20/2017

5. Principle of PGF2a Use Regress active corpus luteum
Only effective on day corpus luteum
Not effective on days:
1 - 4 (CL not responsive)
(CL already regressed)
Updated: 4/20/2017

6. Updated: 4/20/2017

7. Lutalyse 1 injection + palpation Heat Check & Breed Inject Lutalyse
to those
with a CL
11 days
1 injection +
palpation
Palpation
to detect CL
Inject Lutalyse to
those not getting
the 1st injection
Heat Check & Breed
Updated: 4/20/2017

8. Principle of PGF2a Use In estrus 2 - 5 days after injection
Heifers ~ 50 hrs
Cows ~ 72 hrs
Updated: 4/20/2017

9. Reasons for Variation in Response
Stage of the follicular wave at time of PGF2a
Day After Ovulation 10
Ovulation
Follicular Size 7
Updated: 4/20/2017

10. Reasons for Variation in Response
Stage of the follicular wave
Follicular Size
PGF2
PGF2
Ovulation 7 10
Day After Ovulation
Updated: 4/20/2017

11. Reasons for Variation in Response
Stage of the follicular wave
Time to response depends on stage of follicular wave!
Follicular Size
PGF2
PGF2
Ovulation 7 10
Day After Ovulation
Updated: 4/20/2017

12. Reasons for Variation in Response (cont.)
Heifers react faster than cows
Follicular growth is faster in heifers
Animals may be pregnant
No CL may be present - Anestrus
Brahman cattle respond poorly to the two injection system of PGF2a
Recommended:
Inject and breed all responders
Inject 2nd treatment 11 days later to all those not bred to 1st injection and breed on estrus detection
This approach also reduces the number of second injections needed!
Updated: 4/20/2017

13. Management Consideration:
Have proper facilities to handle animals
Good reproductive records
Have enough A.I. technician help
One technician/100 cows will cause problems
Should be around cows/technician
Anestrus cows don’t respond to PGF2a
No CL!!!!!!
Be sure cows & heifers cycling
Use good fertility semen
Updated: 4/20/2017

14. Breeding with Prostaglandins:
Conception Rate
1. Breed 80 hours after 2nd injection
2. Breed based on estrus after PGF2a
3. Control cows bred based on estrus %
67%
75%
Updated: 4/20/2017

15. Improving Ovulation Synchronization
48 hours after PGF2a
Give GnRH
Cause LH surge; achieved slight increase in conception rates
3 - 4 %
Cystorelin (GnRH Analogue)
Updated: 4/20/2017

16. Use of Progestogens Principle:
Maintain the cow under the influence of progesterone until corpus luteum regresses, remove progesterone -
animal respond to progesterone with estrus 2-5 days later.
Administration:
Injection
Feed
Implant
Pessary or Control Internal Drug Release (CIDR)
This does not regress the CL!!!!
Time Consuming
Mix in ration
Place in ear
Place in
Vagina
Updated: 4/20/2017

17. Updated: 4/20/2017

18. Updated: 4/20/2017

19. EAZI-BREED CIDR Beef Cow Lutyalytic to day 1-4 CL Day 6 Day 7 Day 8
7 Days
Insert CIDR
with CIDIROL
capsule
Inject PG
Remove
CIDR
Inject
2mL
CIDIROL
Detect Estrus or
Inseminate
Fixed-time
50 hours
From CIDIROL
Estrogen
Triggers GnRH surge
Updated: 4/20/2017

20. Initiation of Puberty in Cattle
Objectives
Start follicular development
FSH or eCG
Progesterone need in order to exhibit estrus in response to follicular estrogen
Give progestin in either feed or vaginal insert
Procedures
Progestin in feed or CDIR for days
Follow with eCG on last day of progestin treatment
Some heifers will ovulate even if don’t give eCG
Updated: 4/20/2017

21. Induction of Ovulation in Postpartum Cows
GnRH on Day postpartum
Luteinizes some follicles to produce progesterone
First ovulation on day 35 and associated with estrus due to progesterone exposure
Ovsynch
Updated: 4/20/2017

22. Ovsynch GnRH PGF2 GnRH Timed AI 8 - 18 hours 7 Days 36 - 48 hours
Updated: 4/20/2017

23. How Does Ovsynch Work? Ovsynch dramatically improves service rate
Ovsynch does not change conception rate
Ovsynch dramatically improves service rate
Updated: 4/20/2017

24. Experimental Design Field trial using lactating dairy cows from three herds in South-central Wisconsin
Treatment:
Description:
Estrus detection with a.m./p.m. AI
Synchronization of ovulation with timed AI
Control (n=166)
Ovsynch (n=167)
Updated: 4/20/2017

25. Methodology Voluntary waiting period = 50 days
Pregnancy diagnosis was determined by ultrasound 32 to 38 days post-AI
Nonpregnant cows remained in the same treatment group until diagnosed pregnant or culled from the herd
Updated: 4/20/2017

26. Updated: 4/20/2017

27. Proportion Not Pregnant
Updated: 4/20/2017

28. Results
Updated: 4/20/2017

29. Results
Preg/Insemination
Updated: 4/20/2017

30. Ovsynch Disadvantages: Advantages: Hormone Costs
Elimination of estrus detection for first postpartum breeding
Timed AI results in conception rates similar to that of AI to a standing estrus
Disadvantages:
Hormone Costs
Can not use on heifers
Updated: 4/20/2017

31. Ewe Estrus Synchronization
Progestin
CIDR
vaginal pessary (sponge)
Updated: 4/20/2017

32. Updated: 4/20/2017

33. Use of Progestin in Sheep
If during the non-breeding season, induce follicular growth at time of CIDR removal
eCG ( IU)
PG600
Product designed for induction of puberty in gilts
contains 400 IU eCG and 200 IU HCG
Fertility in the breeding season is good
Use 1 ram / 10 ewes
Fixed time insemination at hours using laproscopic technique
Updated: 4/20/2017

34. Ewe Estrus Synchronization
PGF2a
Use in breeding season only
2 injections of Lutalyse (20 mg ) 9 days apart
No effect if ewe anestrus
Updated: 4/20/2017

35. Induction of Puberty in the Ewe Lamb
Progesterone days and eCG on last day of treatment
Can give PG 600 in place of eCG alone
Seasonal
Decrease light to simulate fall
Give melatonin
Postpartum
If attempting to have 2 lamb crops, treat like induction of puberty
Induction of Ovulation in Anestrous Ewes
Updated: 4/20/2017

36. Sow Estrus Synchronization
PGF2a
Will not cause regression of the CL until day 12 of the cycle
Not of practical use
Progestins - Altrenogest
Common progestins (MGA) will synchronize estrus but cause ovarian cysts
Regumate
Product developed for horses
Give 20 mg/day on feed for 18 days
Estrus is days after stop giving Regumate
Only minor incidence of cysts
Cost is $5 - $10/day
Updated: 4/20/2017

37. Sow Estrus Synchronization (cont.)
Wean piglets
3 - 6 days come into estrus
Updated: 4/20/2017

38. Induction of Puberty in Gilts
Prepubertal (noncycling)
PG 600
400 IU eCG and 200 IU HCG
Gilts can not be cycling
Need to be > 5.5 months of age
Gilts express heat days following treatment
Updated: 4/20/2017

39. Mare Estrus Synchronization
PGF2a
Works on CL >5 days of age and mare in diestrus
Lutalyse
1 ml/500 lbs. body weight
Mare CL more sensitive than cow’s
Side effects can be sever in mare
Sweating
Adominal cramps, increased motility of GI tract and/or colic
Increased heart rate
Muscle weakness and balance problems
All side effects begin at minutes and last until 60 minutes after injection
Updated: 4/20/2017

40. Mare Estrus Synchronization (cont.)
Ovulation in days
Reasons for treatment
Synchronize estrus/ovulation for artificial insemination or embryo transfer
Prolonged diestrus - failure of CL to regress
May remain for weeks
Low grade uterine infection
Embryo may have died but CL did not regress
May treat all mares entering a breeding farm
Shortens time to estrus and breeding
Updated: 4/20/2017

41. Mare Estrus Synchronization (cont.)
Progestins
Regumate
Oral progestin
Give 1 ml / 100 lbs body weight
Treatment
Feed daily for days
On last day give PGF2a
Will be in heat in days but ovulation not until day 8 after treatment
Uses
Synchronize estrus/ovulation for breeding
Reduce number of mares in heat on any one day to better utilize a stallion over time.
Suppress estrus in a performance mare
Updated: 4/20/2017

42. Induction of Ovulation in Anestrus Mares
Seasonal
Increase light exposure
16 hours light / day (takes days)
Postpartum
Breed at foal heat
Provide adequate nutrition and don’t see lactational anestrus
Updated: 4/20/2017