estrous synchronization superovulation and … utilization e method pre-pubertal heifers post-partum...

Estrous SynchronizationEstrous SynchronizationSuperovulationSuperovulation

andandEmbryo TransferEmbryo Transfer

Estrous SynchronizationEstrous Synchronization

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

Hormones associated with reproduction

LH & FSH

Progesterone

Estrogen

Prostaglandin

Why synchronize?Why synchronize?

Group females for parturition (calving Group females for parturition (calving interval)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 wean Calves produced early in season will wean heavier because they are olderheavier because they are older

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

maintaining 365 d calving interval the next maintaining 365 d calving interval the next yearyear

Basis for Synchronization of Basis for Synchronization of EstrusEstrus

Manipulate life span of CLManipulate life span of CL

Manipulate growth of follicles and timing of Manipulate growth of follicles and timing of ovulationovulation

Utiliza tionT radename

Method

Pre -pub e rtal h e ife rsPo st-partum o rAn e stro us fe m ale s

MGACIDR

Pro g e stin s

Cyc lin g fe m ale sEstrum ateLutalysePro stam ate

Pro stag lan d in s

Mature fe m ale sCysto re linFe rtag yl

Go n ad o tro pin s

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 that stimulates the release of LH and FSH that stimulates follicular developmentstimulates follicular development

Protocols include Ovsynch and CosynchProtocols include Ovsynch and Cosynch

Synchronization methodsSynchronization methods

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

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

– Can expect estrus within two days following Can expect estrus within two days following injectioninjection

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

Synchronization methodsSynchronization methods

ProgestinsProgestins Form of progesterone that extends the Form of progesterone that extends the

period of time progesterone is present period of time progesterone is present and prevents animal from coming into and prevents animal from coming into heatheat

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

Synchronization methods: Synchronization methods: drug trade names and effectivenessdrug trade names and effectiveness

*Cycling cows or heifers*Anestrous cows or heifers∞Mares

MGA*CIDR*Regumate∞

Progestins

*Cycling cows or heifers∞Cycling mares

Lutalyse*Estrumate*Prostamate*Equimate∞

Prostaglandins

Female “type” for drug effectiveness

Trade name

Method

* Cattle ∞Equine ^Swine

Synchronization methods:Synchronization methods:drug trade names and effectivenessdrug trade names and effectiveness

^Peri-pubertal gilts

PG600^PlacentalGonadotropins

*Postpartum cows*Anestrous cows∞Cycling mares

Cystorelin*Fertagyl*Ovuplant∞

Gonadotropin Releasing Hormones

Female “Type” for drug effectiveness

Trade name

Method

* Cattle ∞Equine ^Swine

Cost $2.50/head

One Injection of PGFOne Injection of PGF AdvantagesAdvantages

– Useful for detection of Useful for detection of estrus in heifers and estrus in heifers and cowscows

– Decreased drug costDecreased drug cost– 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 0 in estrus during days 0 to 10to 10

– Poor degree of Poor degree of synchrony on females synchrony on females that return to estrusthat return to 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


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

– Can use fixed Can use fixed insemination time after insemination time after 22ndnd injection injection

LimitationsLimitations– Females must have Females must have

functional CLfunctional CL– Length of estrus Length of estrus

detectiondetection– Administration of PGF Administration of PGF

will cause abortion in will cause 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 in Can hasten cyclicity in

anestrous femalesanestrous females

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


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

– High pregnancy ratesHigh pregnancy rates

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 AIfacilitate fixed time AI

Cost $9.00/head

Cost $9.00/head

GnRH GnRH AdvantagesAdvantages

– Higher and tighter Higher and tighter rate of estrus rate of estrus synchrony compared synchrony compared to PGF protocolsto PGF protocols

– Allows for estrus Allows for estrus detection or timed AIdetection or timed AI

LimitationsLimitations– Higher cost due to Higher cost due to

hormone injectionshormone injections– Increase of time and Increase of time and

laborlabor– Not recommended for Not recommended for

use in heifersuse in heifers

Synchronization in the MareSynchronization in the Mare Products used: Equimate, Estrumate, LutalyseProducts used: Equimate, Estrumate, Lutalyse

When administered in diestrus, expect ovulation in 7-12 When administered in diestrus, expect ovulation in 7-12 daysdays

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

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

Prostaglandin should be given after day 6Prostaglandin should be given after day 6 hCG can be given to mares resulting in immediate hCG can be given to mares resulting in immediate

ovulationovulation

Synchronization in the SowSynchronization in the Sow Prostaglandin will not cause Prostaglandin will not cause

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

Common progestins will Common progestins will synchronize estrus but synchronize estrus but cause ovarian cystscause ovarian cysts

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

Noncycling gilts can be Noncycling gilts can be synchronized with P.G. synchronized with P.G. 600 (400 IU eCG and 200 600 (400 IU eCG and 200 IU hCG)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 dam Removal of embryos from biological dam (donor) and placement into a surrogate (donor) and placement into a surrogate dam (recipient) for differentiation, growth dam (recipient) for differentiation, growth and birthand 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 distancesTransport genetics across long distances 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 femaleArtificial insemination of the donor female Recovery of embryos from the donorRecovery of embryos from the donor Maintenance of embryosMaintenance of embryos Transfer of embryos to recipient femaleTransfer of embryos to recipient female

SuperovulationSuperovulation

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

8 to 10 ovulations8 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 gonadotropin; eCG)PMSG (pregnant mare serum gonadotropin; eCG)– [Long half-life ~ 2 - 4 days][Long half-life ~ 2 - 4 days]– Not approved for use in commercial SOET in the US. Not approved for use in commercial SOET in the US.

Used frequently for research in Europe.Used frequently for research in Europe.

FSH dosage for superovulation of FSH dosage for superovulation of cattlecattle

20 mg22 mg28 mgTotal

2 mg2 mg2 mg2 mg2 mg2 mgDay 4


3 mg3 mg3 mg3 mg4 mg4 mg Day 2


PMAMPMAMPMAM

HeifersBos IndicusBos Taurus

Steps of Embryo Transfer in Steps of Embryo Transfer in CowsCows

1.1. Synchronization of recipients with donorSynchronization of recipients with donor

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

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

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

1.1. Superovulation of donor femaleSuperovulation of donor female

GoalGoal: hyperstimulate ovaries with : hyperstimulate ovaries with gonadotropinsgonadotropins

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

HowHow: inject donor with FSH: inject donor with FSH


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

GoalGoal: to generate the best fertilization rates and : to generate the best fertilization rates and genetic combinations possiblegenetic 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


1.1. Recovery and identification of viable embryosRecovery and identification of viable embryos

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

ReasonReason: to recover viable embryos: to recover viable embryos

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


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

GoalGoal: to deposit a potentially viable embryo into the : to deposit a potentially viable embryo into the uterine horn of each recipientuterine 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 horn : a single embryo is placed into the uterine horn (ipsilateral to the CL) using a transfer pipette(ipsilateral to the CL) using a transfer pipette


Embryo GradingEmbryo Grading Criteria for classifying Criteria for classifying

embryos embryos

– Even number of cellsEven number of cells– uniform divisionuniform division– 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

estrous synchronization superovulation and … utilization e method pre-pubertal heifers post-partum...

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