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

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

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

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

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) Updated: 4/20/2017

Updated: 4/20/2017

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

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

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

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

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

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

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 don’t respond to PGF2a No CL!!!!!! Be sure cows & heifers cycling Use good fertility semen Updated: 4/20/2017

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 31 - 80% 67% 75% Updated: 4/20/2017

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

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

Updated: 4/20/2017

Updated: 4/20/2017

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

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 don’t give eCG Updated: 4/20/2017

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 Updated: 4/20/2017

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

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

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

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

Updated: 4/20/2017

Proportion Not Pregnant Updated: 4/20/2017

Results Updated: 4/20/2017

Results Preg/Insemination Updated: 4/20/2017

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

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

Updated: 4/20/2017

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 Updated: 4/20/2017

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

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 Updated: 4/20/2017

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 Updated: 4/20/2017

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

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 3 - 4 days following treatment Updated: 4/20/2017

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 5 - 10 minutes and last until 60 minutes after injection Updated: 4/20/2017

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 Updated: 4/20/2017

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 Updated: 4/20/2017

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 don’t see lactational anestrus Updated: 4/20/2017