Estrous SynchronizationEstrous SynchronizationSuperovulationSuperovulation

andandEmbryo TransferEmbryo Transfer

Estrous SynchronizationEstrous Synchronization

A management technique that makes A management technique that makes use of hormones to control or use of hormones to control or reschedule the estrous cyclereschedule the estrous cycle

Hormones associated with reproduction

LH & FSH

Progesterone

Estrogen

Prostaglandin

Why synchronize?Why synchronize?

Group females for parturition Group females for parturition (calving interval)(calving interval)

Shorten breeding seasonShorten breeding season Reduce estrus detectionReduce estrus detection

Advantages of implementing a Advantages of implementing a synchronization programsynchronization program

Calves produced early in season will Calves produced early in season will wean heavier because they are olderwean heavier because they are older

Cows require 40-60 days to recover Cows require 40-60 days to recover from calving before next breedingfrom calving before next breeding– Cows that bred earlier have better Cows that bred earlier have better

chance of maintaining 365 d calving chance of maintaining 365 d calving interval the next yearinterval the next year

Basis for Synchronization of Basis for Synchronization of EstrusEstrus

Manipulate life span of CLManipulate life span of CL

Manipulate growth of follicles and Manipulate growth of follicles and timing of ovulationtiming of ovulation

MethodMethod TradenaTradenameme

UtilizationUtilization

GonadotropinsGonadotropins CystorelinCystorelin

FertagylFertagylMature femalesMature females

ProstaglandinsProstaglandins EstrumateEstrumate

LutalyseLutalyse

ProstamatProstamatee

Cycling femalesCycling females

ProgestinsProgestins MGAMGA

CIDRCIDRPre-pubertal Pre-pubertal heifersheifers

Post-partum orPost-partum or

Anestrous Anestrous femalesfemales

Synchronization Methods

Synchronization MethodsSynchronization Methods

Gonadotropins(GnRH protocols)Gonadotropins(GnRH protocols)

Naturally occurring hormone that Naturally occurring hormone that stimulates the release of LH and FSH stimulates the release of LH and FSH that stimulates follicular developmentthat stimulates follicular development

Protocols include Ovsynch and Protocols include Ovsynch and CosynchCosynch

Synchronization methodsSynchronization methods

ProstaglandinsProstaglandins– Naturally occurring hormone that causes Naturally occurring hormone that causes

regression of the CL (luteolysis) and regression of the CL (luteolysis) and decreases progesterone secretion which decreases progesterone secretion which results in a return to estrusresults in a return to estrus

– Can expect estrus within two days Can expect estrus within two days following injectionfollowing injection

– Protocols include PGF one-shot method Protocols include PGF one-shot method and PGF two-shot methodand PGF two-shot method

Synchronization methodsSynchronization methods

ProgestinsProgestins Form of progesterone that extends Form of progesterone that extends

the period of time progesterone is the period of time progesterone is present and prevents animal from present and prevents animal from coming into heatcoming into heat

Protocols include MGA+prostaglandin Protocols include MGA+prostaglandin and CIDR and CIDR

Synchronization methods: Synchronization methods: drug trade names and drug trade names and

effectivenesseffectivenessMethodMethod Trade Trade

namenameFemale “type” for Female “type” for drug effectivenessdrug effectiveness

ProstaglandinsProstaglandins Lutalyse*Lutalyse*

Estrumate*Estrumate*

Prostamate*Prostamate*

EquimateEquimate∞∞

*Cycling cows or heifers*Cycling cows or heifers∞∞Cycling maresCycling mares

ProgestinsProgestins MGA*MGA*

CIDR*CIDR*

RegumateRegumate∞∞

*Cycling cows or heifers*Cycling cows or heifers

*Anestrous cows or heifers*Anestrous cows or heifers∞∞MaresMares

* Cattle ∞Equine ^Swine

Synchronization methods:Synchronization methods:drug trade names and drug trade names and

effectivenesseffectivenessMethodMethod Trade Trade

namenameFemale “Type” for Female “Type” for drug effectivenessdrug effectiveness

Gonadotropin Gonadotropin Releasing Releasing HormonesHormones

Cystorelin*Cystorelin*

Fertagyl*Fertagyl*

OvuplantOvuplant∞∞

*Postpartum cows*Postpartum cows

*Anestrous cows*Anestrous cows∞∞Cycling maresCycling mares

PlacentalPlacental

GonadotropinsGonadotropinsPG600^PG600^ ^Peri-pubertal gilts ^Peri-pubertal gilts

* Cattle ∞Equine ^Swine

Cost $2.50/head

One Injection of PGFOne Injection of PGF

AdvantagesAdvantages– Useful for detection Useful for detection

of estrus in heifers of estrus in heifers and cowsand cows

– Decreased drug Decreased drug costcost

– Limited animal Limited animal handlinghandling

LimitationsLimitations– 10-25% of females 10-25% of females

may not be detected may not be detected in estrus during days in estrus during days 0 to 100 to 10

– Poor degree of Poor degree of synchrony on synchrony on females that return females that return to estrusto estrus

– Must have CLMust have CL– Length of estrus Length of estrus

detectiondetection– AbortionAbortion

Cost $4.70/head

Two Injections of PGFTwo Injections of PGF

AdvantagesAdvantages– Useful for detection Useful for detection

of estrus in heifers of estrus in heifers and cowsand cows

– Tighter synchrony Tighter synchrony than one injection than one injection methodmethod

– Can use fixed Can use fixed insemination time insemination time after 2after 2ndnd injection injection

LimitationsLimitations– Females must have Females must have

functional CLfunctional CL– Length of estrus Length of estrus

detectiondetection– Administration of Administration of

PGF will cause PGF will cause abortion in abortion in pregnant animalspregnant animals

Cost $8.00/head

MGA and ProstaglandinMGA and Prostaglandin

AdvantagesAdvantages– Proven system for Proven system for

heifersheifers– Inexpensive methodInexpensive method– Can hasten cyclicity Can hasten cyclicity

in anestrous in anestrous femalesfemales

LimitationsLimitations– Length of programLength of program– Must have appropriate Must have appropriate

feeding space to allow feeding space to allow efficient consumptionefficient consumption

– Estrus synchronization Estrus synchronization may be variablemay be variable

– Must ensure uniform Must ensure uniform daily consumption of daily consumption of feed supplement prior feed supplement prior to and during oral to and during oral administration of MGAadministration of MGA

Cost $14.00/head

CIDRCIDR

AdvantagesAdvantages– Useful for detection Useful for detection

of estrus in heifers of estrus in heifers and cowsand cows

– Induces cyclicity in Induces cyclicity in a percentage of a percentage of anestrous cattleanestrous cattle

– High pregnancy High pregnancy ratesrates

LimitationsLimitations– Possible retention Possible retention

failure of CIDRfailure of CIDR– Cost per treatment Cost per treatment

may be higher than may be higher than other methodsother methods

– An additional day of An additional day of processing for processing for hormone treatment hormone treatment would be required to would be required to facilitate fixed time facilitate fixed time AIAI

Cost $9.00/head

Cost $9.00/head

GnRH GnRH

AdvantagesAdvantages– Higher and tighter Higher and tighter

rate of estrus rate of estrus synchrony synchrony compared to PGF compared to PGF protocolsprotocols

– Allows for estrus Allows for estrus detection or timed detection or timed AIAI

LimitationsLimitations– Higher cost due to Higher cost due to

hormone injectionshormone injections– Increase of time Increase of time

and laborand labor– Not recommended Not recommended

for use in heifersfor use in heifers

Synchronization in the MareSynchronization in the Mare

Products used: Equimate, Estrumate, LutalyseProducts used: Equimate, Estrumate, Lutalyse

When administered in diestrus, expect ovulation When administered in diestrus, expect ovulation in 7-12 daysin 7-12 days

If 30-35mm follicle is present, expect ovulation in If 30-35mm follicle is present, expect ovulation in 2-4 days2-4 days

Will only work when fully functional CL is presentWill only work when fully functional CL is present ““short cycling” refers to restarting the estrous short cycling” refers to restarting the estrous

cycle earlycycle earlyProstaglandin should be given after day 6Prostaglandin should be given after day 6

hCG can be given to mares resulting in hCG can be given to mares resulting in immediate ovulationimmediate ovulation

Synchronization in the SowSynchronization in the Sow

Prostaglandin will not Prostaglandin will not cause CL regression cause CL regression until day 12 of cycle until day 12 of cycle because LH binds to because LH binds to luteal cell receptor with luteal cell receptor with strong affinity following strong affinity following ovulation and is not ovulation and is not released until day 12. released until day 12. Repeated injections Repeated injections over two to three days over two to three days will regress CL sooner, will regress CL sooner, but is not practical.but is not practical.

Common progestins Common progestins will synchronize estrus will synchronize estrus but cause ovarian but cause ovarian cystscysts

Regumate has been Regumate has been found to be effectivefound to be effective

Noncycling gilts can Noncycling gilts can be synchronized with be synchronized with P.G. 600 (400 IU eCG P.G. 600 (400 IU eCG and 200 IU hCG)and 200 IU hCG)

Synchronization in the EweSynchronization in the Ewe

Most common protocols use either use Most common protocols use either use prostaglandins or CIDRprostaglandins or CIDR

Embryo TransferEmbryo Transfer

Removal of embryos from biological Removal of embryos from biological dam (donor) and placement into a dam (donor) and placement into a surrogate dam (recipient) for surrogate dam (recipient) for differentiation, growth and birthdifferentiation, growth and birth

Purpose of Embryo TransferPurpose of Embryo Transfer

Increase productivity of genetically Increase productivity of genetically superior donorssuperior donors

Maximize use of valuable semenMaximize use of valuable semen Transport genetics across long Transport genetics across long

distancesdistances Production of identical offspring by Production of identical offspring by

embryo splittingembryo splitting– (potentially valuable as research animals)(potentially valuable as research animals)

Limitations of Embryo TransferLimitations of Embryo Transfer

ExpensiveExpensive Labor intensiveLabor intensive Requires extensive training and Requires extensive training and

experienceexperience

Successful Embryo Transfer Successful Embryo Transfer Requires:Requires:

SuperovulationSuperovulation Artificial insemination of the donor Artificial insemination of the donor

femalefemale Recovery of embryos from the donorRecovery of embryos from the donor Maintenance of embryosMaintenance of embryos Transfer of embryos to recipient Transfer of embryos to recipient

femalefemale

SuperovulationSuperovulation

Treatment of a female with Treatment of a female with gonadotropins (generally FSH) to gonadotropins (generally FSH) to increase the number of oocytes that increase the number of oocytes that are selected to become dominant are selected to become dominant follicles and ovulatefollicles and ovulate– a typical treatment response in cattle a typical treatment response in cattle

would be 8 to 10 ovulationswould be 8 to 10 ovulations

Superovulation ProceduresSuperovulation Procedures

Hormones used for SuperovulationHormones used for Superovulation FSH (follicle stimulating hormone)FSH (follicle stimulating hormone)

– [Short half-life ~2 hours][Short half-life ~2 hours]– Used for commercial SOETUsed for commercial SOET

PMSG (pregnant mare serum PMSG (pregnant mare serum gonadotropin; eCG)gonadotropin; eCG)– [Long half-life ~ 2 - 4 days][Long half-life ~ 2 - 4 days]– Not approved for use in commercial SOET in Not approved for use in commercial SOET in

the US. Used frequently for research in Europe.the US. Used frequently for research in Europe.

FSH dosage for superovulation FSH dosage for superovulation of cattleof cattle

Bos TaurusBos Taurus Bos IndicusBos Indicus HeifersHeifers

AMAM PMPM AMAM PMPM AMAM PMPM

Day Day 11

5 mg5 mg 5 mg5 mg 4 mg4 mg 4 mg4 mg 3 mg3 mg 3 mg3 mg

Day Day 22

4 mg 4 mg 4 mg4 mg 3 mg3 mg 3 mg3 mg 3 mg3 mg 3 mg3 mg

Day Day 33

3 mg3 mg 3 mg3 mg 2 mg2 mg 2 mg2 mg 2 mg2 mg 2 mg2 mg

Day Day 44

2 mg2 mg 2 mg2 mg 2 mg2 mg 2 mg2 mg 2 mg2 mg 2 mg2 mg

TotalTotal 28 mg28 mg 22 mg22 mg 20 mg20 mg

Steps of Embryo Transfer in Steps of Embryo Transfer in CowsCows

1.1. Synchronization of recipients with Synchronization of recipients with donordonor

GoalGoal: want donor and recipient to be in : want donor and recipient to be in same stage of estrous cyclesame stage of estrous cycle

ReasonReason: preparation of recipient uterus : preparation of recipient uterus to support embryogenesisto support embryogenesis

HowHow: treat recipient with synchronization : treat recipient with synchronization protocol that induces estrus to occur at protocol that induces estrus to occur at same time as the donorsame time as the donor

2.2. Superovulation of donor femaleSuperovulation of donor female

GoalGoal: hyperstimulate ovaries with : hyperstimulate ovaries with gonadotropinsgonadotropins

ReasonReason: provide higher than normal : provide higher than normal numbers of follicles that will ovulatenumbers of follicles that will ovulate

HowHow: inject donor with FSH: inject donor with FSH

Steps of Embryo Transfer in Steps of Embryo Transfer in CowsCows

3.3. Inseminate donor with semen from Inseminate donor with semen from genetically superior bullgenetically superior bull

GoalGoal: to generate the best fertilization rates : to generate the best fertilization rates and genetic combinations possibleand genetic combinations possible

ReasonReason: enhance rate of genetic progress: enhance rate of genetic progress

HowHow: utilize highly fertile semen and trained : utilize highly fertile semen and trained inseminatorsinseminators

Steps of Embryo Transfer in Steps of Embryo Transfer in CowsCows

4.4. Recovery and identification of viable Recovery and identification of viable embryosembryos

GoalGoal: nonsurgically collect (flush) embryos : nonsurgically collect (flush) embryos from donor for transferfrom donor for transfer

ReasonReason: to recover viable embryos: to recover viable embryos

HowHow: block with local anesthetic to relax : block with local anesthetic to relax rectum, at day 6-8 a Foleys catheter is inserted rectum, at day 6-8 a Foleys catheter is inserted into uterus and inflated to prevent retrograde flow into uterus and inflated to prevent retrograde flow of flushing medium, introduce medium, lavage of flushing medium, introduce medium, lavage uterus and collect fluiduterus and collect fluid

Steps of Embryo Transfer in Steps of Embryo Transfer in CowsCows

5.5. Transfer of viable embryos into Transfer of viable embryos into synchronized recipientssynchronized recipients

GoalGoal: to deposit a potentially viable embryo into : to deposit a potentially viable embryo into the uterine horn of each recipientthe uterine horn of each recipient

ReasonReason: to achieve pregnancy in each recipient: to achieve pregnancy in each recipient

HowHow: a single embryo is placed into the uterine : a single embryo is placed into the uterine horn (ipsilateral to the CL) using a transfer horn (ipsilateral to the CL) using a transfer pipettepipette

Steps of Embryo Transfer in Steps of Embryo Transfer in CowsCows

Embryo GradingEmbryo Grading

Criteria for classifying Criteria for classifying embryos embryos

– Even number Even number of cellsof cells

– uniform uniform divisiondivision

– healthy zona healthy zona pellucidapellucida

Embryo QualityEmbryo Quality

1 – Excellent1 – Excellent

2 – Good 2 – Good 3 – Fair 3 – Fair

4 – Poor4 – Poor

5 – Degenerate5 – Degenerate