Estrous Synchronization (Ovulation Induction) and Ovsynch

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Estrous Synchronization (Ovulation Induction)and
Ovsynch

• John Parrish

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Learning Objective
To understand how estrus synchronization and
Ovsynch work along with how to use it
successfully.
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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.
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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
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Principle of PGF2a Use

• Regress active corpus luteum
• Only effective on day 5 - 17 corpus luteum
• Not effective on days
• 1 - 4 (CL not responsive)
• 18 - 21 (CL already regressed)

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Lutalyse
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
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Principle of PGF2a Use

• In estrus 2 - 5 days after injection
• Heifers 50 hrs
• Cows 72 hrs

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Reasons for Variation in Response

• Stage of the follicular wave at time of PGF2a

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Reasons for Variation in Response

• Stage of the follicular wave

Follicular Size
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Ovulation
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Day After Ovulation
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Reasons for Variation in Response

• Stage of the follicular wave

Time to response depends on stage of follicular
wave!
Follicular Size
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Ovulation
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Day After Ovulation
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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!

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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 30-50 cows/technician
• Anestrus cows dont respond to PGF2a
• No CL!!!!!!
• Be sure cows heifers cycling
• Use good fertility semen

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Breeding with Prostaglandins
Conception Rate
31 - 80

• 1. Breed 80 hours after 2nd injection
• 2. Breed based on estrus after PGF2a
• 3. Control cows bred based on estrus

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Improving Ovulation Synchronization

• 48 hours after PGF2a
• Give GnRH
• Cause LH surge achieved slight increase in
  conception rates
• 3 - 4

Cystorelin (GnRH Analogue)
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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
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EAZI-BREED CIDR
Beef Cow
Day 9-11
Day 6
Day 7
Day 8
7 Days
Insert CIDR with CIDIROL capsule
Remove CIDR
Detect Estrus or Inseminate Fixed-time 50
hours From CIDIROL
Inject PG
Inject 2mL CIDIROL
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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 7 - 21 days
• Follow with eCG on last day of progestin
  treatment
• Some heifers will ovulate even if dont give eCG

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Induction of Ovulation in Postpartum Cows

• GnRH on Day 12 - 14 postpartum
• Luteinizes some follicles to produce progesterone
• First ovulation on day 35 and associated with
  estrus due to progesterone exposure
• Ovsynch

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Ovsynch
GnRH
PGF2?
GnRH
7 Days
36 - 48 hours
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How Does Ovsynch Work?

• Ovsynch does not change conception rate
• Ovsynch dramatically improves service rate

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Experimental DesignField 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 (n166)
Ovsynch (n167)
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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

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Proportion Not Pregnant
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Results
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Results
Preg/Insemination
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Ovsynch

• Advantages
• 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

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Ewe Estrus Synchronization

• Progestin
• CIDR
• vaginal pessary (sponge)

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Use of Progestin in Sheep

• If during the non-breeding season, induce
  follicular growth at time of CIDR removal
• eCG (400 - 800 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 48-52 hours using
  laproscopic technique

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Ewe Estrus Synchronization

• PGF2a
• Use in breeding season only
• 2 injections of Lutalyse (20 mg ) 9 days apart
• No effect if ewe anestrus

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Induction of Puberty in the Ewe Lamb

• Progesterone 12 - 14 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
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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 4 - 8 days after stop giving Regumate
• Only minor incidence of cysts
• Cost is 5 - 10/day

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Sow Estrus Synchronization (cont.)

• Wean piglets
• 3 - 6 days come into estrus

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Induction of Puberty in Gilts

• Prepubertal (noncycling)
• PG 600
• 400 IU eCG and 200 IU HCG
• Gilts can not be cycling
• Need to be gt 5.5 months of age
• Gilts express heat 3 - 4 days following treatment

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Mare Estrus Synchronization

• PGF2a
• Works on CL gt5 days of age and mare in diestrus
• Lutalyse
• 1 ml/500 lbs. body weight
• Mare CL more sensitive than cows
• 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 5 - 10 minutes and last
  until 60 minutes after injection

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Mare Estrus Synchronization (cont.)

• Ovulation in 8 - 9 days
• Reasons for treatment
• Synchronize estrus/ovulation for artificial
  insemination or embryo transfer
• Prolonged diestrus - failure of CL to regress
• May remain for 3 - 4 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

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Mare Estrus Synchronization (cont.)

• Progestins
• Regumate
• Oral progestin
• Give 1 ml / 100 lbs body weight
• Treatment
• Feed daily for 12 - 14 days
• On last day give PGF2a
• Will be in heat in 3 - 4 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

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Induction of Ovulation in Anestrus Mares

• Seasonal
• Increase light exposure
• 16 hours light / day (takes 30 - 60 days)
• Postpartum
• Breed at foal heat
• Provide adequate nutrition and dont see
  lactational anestrus