EMBRYO TRANSFERstaff.unila.ac.id/gnugroho/files/2020/04/Embryo-Transfer-2.pdf · In cattle and horses, embryos for commercial purposes are usually recovered 6 to 9 days after estrus

EMBRYOTRANSFER

Photo from Wikipedia.

EMBRYOTRANSFER

Introduction

Embryo transfer is a processby which an embryo iscollected from a donor femaleand transferred into a recipientfemale where the embryocompletes its development.


Embryo transfer is a processby which an embryo iscollected from a donor femaleand transferred into a recipientfemale where the embryocompletes its development.

Through the use of embryotransfer, a genetically superiorfemale produces more offspringthan she could by naturalreproduction, thus maximizingher genetic abilities.


Through the use of embryotransfer, a genetically superiorfemale produces more offspringthan she could by naturalreproduction, thus maximizingher genetic abilities.

Embryo transfer is profitable forproducers of registeredpurebred animals and is used inseveral species of domesticanimals, especially cattle,horses, goats, and sheep.

It has also been used in non-domestic species, such as deer,elk, bison, and wildcats.


Embryo transfer is profitable forproducers of registeredpurebred animals and is used inseveral species of domesticanimals, especially cattle,horses, goats, and sheep.

It has also been used in non-domestic species, such as deer,elk, bison, and wildcats.

The first embryo transfer wasperformed in 1890 at theUniversity of Cambridge usingrabbits.

It was not until 1951 that thetechnique was successfully usedin cattle and has since becomea more popular procedure forother animal species.


The first embryo transfer wasperformed in 1890 at theUniversity of Cambridge usingrabbits.

It was not until 1951 that thetechnique was successfully usedin cattle and has since becomea more popular procedure forother animal species.

As long as embryo transferremains a key step in many ofthe developing technologies,such as prenatal sex selection,the commercial embryo transferindustry will continue to grow.


As long as embryo transferremains a key step in many ofthe developing technologies,such as prenatal sex selection,the commercial embryo transferindustry will continue to grow.


Donor, Superovulation,and Insemination

The producer should consider thefollowing factors when developingan embryo transfer program:

• Selection of donor females,

• Superovulation, and

• Insemination.Photo from Wikipedia.

The producer should consider thefollowing factors when developingan embryo transfer program:

• Selection of donor females,

• Superovulation, and

• Insemination.

Donor Female Selection

The donor female selected forembryo transfer should haveoutstanding genetics.

She should also be healthy andreproductively sound.


Donor Female Selection

The donor female selected forembryo transfer should haveoutstanding genetics.

She should also be healthy andreproductively sound.

Superovulation

Superovulation refers to therelease of many oocytes (eggs)during a single estrus period.

Normally, only one follicleruptures in cows and maresreleasing one ovum and twofollicles rupture in ewesreleasing two ovum.


Superovulation refers to therelease of many oocytes (eggs)during a single estrus period.

Normally, only one follicleruptures in cows and maresreleasing one ovum and twofollicles rupture in ewesreleasing two ovum.

Superovulation can be achievedthrough treatment withgonadotropins.

Most embryo transfer donorsare treated with folliclestimulating hormone (FSH) toinduce the maturation andovulation of a larger thannormal number of oocytes.


Superovulation can be achievedthrough treatment withgonadotropins.

Most embryo transfer donorsare treated with folliclestimulating hormone (FSH) toinduce the maturation andovulation of a larger thannormal number of oocytes.

For example, a single treatmentof a cow results in 0 to 20 moreembryos, with an average ofseven normal embryos.


When attempts are made torecover a single ovum from anon-superovulated cow at everyestrus, the 12-month yieldaverages 5 calves.

In contrast, when a donor issuperovulated three times, theyield ranges from 9 to 12 calves.


When attempts are made torecover a single ovum from anon-superovulated cow at everyestrus, the 12-month yieldaverages 5 calves.

In contrast, when a donor issuperovulated three times, theyield ranges from 9 to 12 calves.

Following embryo transfer,superovulated ova result innormal offspring with successrates similar to those achievedwith normally ovulated ova.


Following embryo transfer,superovulated ova result innormal offspring with successrates similar to those achievedwith normally ovulated ova.

Adequate procedures exist forsuperovulation of laboratoryand livestock species, exceptfor horses.

A mare does not respondsatisfactorily to superovulatorytreatment, thus maximizationof reproduction in mares mustbe achieved by collectingembryos at each estrus.


Adequate procedures exist forsuperovulation of laboratoryand livestock species, exceptfor horses.

A mare does not respondsatisfactorily to superovulatorytreatment, thus maximizationof reproduction in mares mustbe achieved by collectingembryos at each estrus.

Insemination

Because superovulation of thedonor female causes therelease of a large number ofeggs over a 24-hour period,many producers choose toinseminate the donor severaltimes to achieve optimalfertilization.


Because superovulation of thedonor female causes therelease of a large number ofeggs over a 24-hour period,many producers choose toinseminate the donor severaltimes to achieve optimalfertilization.

Embryo Recovery

Success of embryo recoverydepends on the age of theembryos, as well as, thetechnical procedure used andthe skill level of the technician.


Success of embryo recoverydepends on the age of theembryos, as well as, thetechnical procedure used andthe skill level of the technician.

With superovulated donors,many follicles never ovulate;others may develop as if theyhad ovulated, but they neverrelease oocytes.


With superovulated donors,many follicles never ovulate;others may develop as if theyhad ovulated, but they neverrelease oocytes.

Furthermore, if the ovariesenlarge greatly in response tosuperovulatory treatment or ifmany ovulations occur, thefimbriae apparently do notgather all of the oocytes intothe oviducts.


Furthermore, if the ovariesenlarge greatly in response tosuperovulatory treatment or ifmany ovulations occur, thefimbriae apparently do notgather all of the oocytes intothe oviducts.

Radically altered endocrine levelsmay occur as a result ofsuperovulatory treatment.

This causes the uterus to becomean unfavorable environment forembryonic development.

The incidence of degenerateembryos may increase duringdays 7 and 8 after estrus.


Radically altered endocrine levelsmay occur as a result ofsuperovulatory treatment.

This causes the uterus to becomean unfavorable environment forembryonic development.

The incidence of degenerateembryos may increase duringdays 7 and 8 after estrus.

It is difficult to count the numberof ovulations in superovulateddonors, even with surgicalexamination.

With non-surgical recoverymethods, the number ofovulations can only be estimatedby palpation.


It is difficult to count the numberof ovulations in superovulateddonors, even with surgicalexamination.

With non-surgical recoverymethods, the number ofovulations can only be estimatedby palpation.

Non-Surgical Recovery

Advances in technology havemade embryo recovery a non-surgical procedure with cattleand horses.

A specially designed catheter(Foley catheter) is used whencollecting embryos using non-surgical methods.


Advances in technology havemade embryo recovery a non-surgical procedure with cattleand horses.

A specially designed catheter(Foley catheter) is used whencollecting embryos using non-surgical methods.


Steps in non-surgical procedurefor embryo recovery:

1. Clean the donor’s genital area.

2. Inject a local anesthetic in therump or hip.

3. After anesthetic takes effect,insert the Foley catheter intothe vagina and through thecervix.


Steps in non-surgical procedurefor embryo recovery:

1. Clean the donor’s genital area.

2. Inject a local anesthetic in therump or hip.

3. After anesthetic takes effect,insert the Foley catheter intothe vagina and through thecervix.

4. Flush out the embryos byforcing fluid from the catheterinto the uterus and collectingit in a special container, whichfilters out the embryos.


4. Flush out the embryos byforcing fluid from the catheterinto the uterus and collectingit in a special container, whichfilters out the embryos.

Surgical Recovery

Unfertilized oocytes forspecialized applications, suchas in-vitro fertilization, must becollected near the time ofovulation from the follicles,surface of the ovary, or oviduct.


Unfertilized oocytes forspecialized applications, suchas in-vitro fertilization, must becollected near the time ofovulation from the follicles,surface of the ovary, or oviduct.

For most applications, embryosare collected anytime betweenfertilization and implantation,but usually after they migrateto the uterus.


For most applications, embryosare collected anytime betweenfertilization and implantation,but usually after they migrateto the uterus.

In cattle and horses, embryosfor commercial purposes areusually recovered 6 to 9 daysafter estrus.

Before this time, non-surgicalrecovery is ineffective.

After 9 days, recovery andpregnancy rates are slightlyreduced, at least with surgicaltransfer of bovine embryos.


In cattle and horses, embryosfor commercial purposes areusually recovered 6 to 9 daysafter estrus.

Before this time, non-surgicalrecovery is ineffective.

After 9 days, recovery andpregnancy rates are slightlyreduced, at least with surgicaltransfer of bovine embryos.

Surgical recovery can be donein all species and is the methodof choice for sheep, goats, andhogs.

Techniques vary slightly withthe species.


Surgical recovery can be donein all species and is the methodof choice for sheep, goats, andhogs.

Techniques vary slightly withthe species.

Embryo Evaluation

After collection, embryos areevaluated for quality using astereoscopic microscope.

Embryos are graded on a scalefrom one (excellent) to four(poor).


After collection, embryos areevaluated for quality using astereoscopic microscope.

Embryos are graded on a scalefrom one (excellent) to four(poor).

Factors considered during theevaluation include:

• Shape,

• Color,

• Texture, and

• Size.


• Shape,

• Color,

• Texture, and

• Size.

Embryos are also classified basedon their stages of development.

Normal embryos will havebetween 2 and 64 cells.


Embryo Storage

Donor embryos can betransferred immediately intorecipients or they can bestored for future use.


Donor embryos can betransferred immediately intorecipients or they can bestored for future use.

Procedures such as embryotransfer, in-vitro fertilization,sex determination, and cloningdepend on maintaining theviability of embryos for hoursto days outside of thereproductive tract.


Procedures such as embryotransfer, in-vitro fertilization,sex determination, and cloningdepend on maintaining theviability of embryos for hoursto days outside of thereproductive tract.

For many applications, thestorage system must not onlymaintain the viability of theembryo, it must also supportcontinued development.


In some cases, it may be desirableto retard the growth of theembryo to a degree approachingsuspended animation, so thatdevelopment can be synchronizedwith later events.

For example, it may be necessaryto store embryos until suitablerecipients become available fortransfer.


In some cases, it may be desirableto retard the growth of theembryo to a degree approachingsuspended animation, so thatdevelopment can be synchronizedwith later events.

For example, it may be necessaryto store embryos until suitablerecipients become available fortransfer.

Short-Term Storage

Embryos can be stored at roomtemperature for one day fordirect transfer from the donorto the recipients.


Embryos can be stored at roomtemperature for one day fordirect transfer from the donorto the recipients.

Embryos must be stored at 5°Cin an appropriate medium, if kept24 to 48 hours.

Most media and culture systemsare adequate for maintaining theviability of the embryo betweendonor and recipient.


Embryos must be stored at 5°Cin an appropriate medium, if kept24 to 48 hours.

Most media and culture systemsare adequate for maintaining theviability of the embryo betweendonor and recipient.

Long-Term Storage

If embryos are to be transportedgreat distances or suitablerecipients are not immediatelyavailable, a long-term storagesystem is essential.

Deep-freezing means thatembryos are stored in liquidnitrogen for a long period of time.


If embryos are to be transportedgreat distances or suitablerecipients are not immediatelyavailable, a long-term storagesystem is essential.

Deep-freezing means thatembryos are stored in liquidnitrogen for a long period of time.

Long-term storage throughfreezing usually results indamage of 30% to 50% of thestored embryos.

Damage is usually caused by icecrystal formation within theembryonic cell.


Long-term storage throughfreezing usually results indamage of 30% to 50% of thestored embryos.

Damage is usually caused by icecrystal formation within theembryonic cell.

Although the average survivalrate of frozen-thawed embryosis approximately 65%, it isprofitable to maintain embryosin long-term storage.


Although the average survivalrate of frozen-thawed embryosis approximately 65%, it isprofitable to maintain embryosin long-term storage.

Transfer of Embryosinto Recipient Cows

Recipients to be implanted withthe collected embryos should behealthy and reproductivelysound.


Recipients to be implanted withthe collected embryos should behealthy and reproductivelysound.

To maximize success rate of thetransfer, the recipient’s estrusshould be in sync with that of thedonor.

Estrus synchronization is importantto establish a uniform uterineenvironment for the embryo;therefore, only one day or lessdifference in estrus between donorand recipient is acceptable.


To maximize success rate of thetransfer, the recipient’s estrusshould be in sync with that of thedonor.

Estrus synchronization is importantto establish a uniform uterineenvironment for the embryo;therefore, only one day or lessdifference in estrus between donorand recipient is acceptable.

Research indicates that there islittle difference in pregnancyrates between natural estrus andinduced estrus recipients.

Induced estrus forsynchronization is accomplishedwith treatments of progestogens,which are synthetic progesteroneproducts.


Research indicates that there islittle difference in pregnancyrates between natural estrus andinduced estrus recipients.

Induced estrus forsynchronization is accomplishedwith treatments of progestogens,which are synthetic progesteroneproducts.

Non-Surgical Transfer of Embryos

For cattle and horses,technicians mainly use non-surgical techniques to recoverand transplant embryos.


For cattle and horses,technicians mainly use non-surgical techniques to recoverand transplant embryos.

Flushed embryos that passinspection are loaded into anAI straw.

An insemination rod is passedthrough the recipient’s cervixand into her uterus (similar toAI procedure).


Flushed embryos that passinspection are loaded into anAI straw.

An insemination rod is passedthrough the recipient’s cervixand into her uterus (similar toAI procedure).

The embryo is expelled into theuterine horn that is on the sameside as the ovulated ovary (tooptimize the embryoimplantation rate).


The embryo is expelled into theuterine horn that is on the sameside as the ovulated ovary (tooptimize the embryoimplantation rate).

Surgical Transfer of Embryos

Embryos in early stages ofdevelopment must be depositedin the oviducts.

This procedure must beperformed surgically.

Surgery is also required foruterine transfers in sheep, goats,and hogs.


Embryos in early stages ofdevelopment must be depositedin the oviducts.

This procedure must beperformed surgically.

Surgery is also required foruterine transfers in sheep, goats,and hogs.

Success of surgical transferdepends on interactions of anumber of factors, including:

• Age and quality of embryos,

• Site of transfer,

• Degree of estrus synchronizationbetween donor and recipients,


Success of surgical transferdepends on interactions of anumber of factors, including:

• Age and quality of embryos,

• Site of transfer,

• Degree of estrus synchronizationbetween donor and recipients,

• Number of embryos transferred,

• In-vitro culture conditions,

• Skill of personnel, and

• Management techniques.


• Number of embryos transferred,

• In-vitro culture conditions,

• Skill of personnel, and

• Management techniques.

Conception rates are up to 5%greater with surgical transfer.

Surgical transfer of normalembryos compares to the first-service pregnancy rates usingartificial insemination.


Conception rates are up to 5%greater with surgical transfer.

Surgical transfer of normalembryos compares to the first-service pregnancy rates usingartificial insemination.

The reproductive tract can beexposed for surgical transfer ofembryos.

Transfer occurs through a midlinelaparotomy (incision through theabdominal wall) with generalanesthesia or through a flankincision with local anesthesia.


The reproductive tract can beexposed for surgical transfer ofembryos.

Transfer occurs through a midlinelaparotomy (incision through theabdominal wall) with generalanesthesia or through a flankincision with local anesthesia.

The midline approach is lesstraumatic to the reproductivetract and permits betterexposure in some animals.

The flank approach, on theother hand, is quicker, lessexpensive, and reduces risk byusing minimum equipment.


The midline approach is lesstraumatic to the reproductivetract and permits betterexposure in some animals.

The flank approach, on theother hand, is quicker, lessexpensive, and reduces risk byusing minimum equipment.

Embryo Survival

The survival rate of the embryo,from implantation to term in therecipient female, ranges from55% to 70%.

Embryo quality is an importantdeterminant of transfer success.


The survival rate of the embryo,from implantation to term in therecipient female, ranges from55% to 70%.

Embryo quality is an importantdeterminant of transfer success.

The most accurate predictor ofsuccess is the stage ofembryonic development.

Recipient females are palpatedwithin one to three monthsafter embryo transfer todiagnose stage of pregnancy.


The most accurate predictor ofsuccess is the stage ofembryonic development.

Recipient females are palpatedwithin one to three monthsafter embryo transfer todiagnose stage of pregnancy.

New TechnologiesEmbryo transfer is a compositetechnology that requiresexpertise in many areas.


Present and emerging technologiesthat build upon current embryotransfer procedures includepredetermination of sex, sexselection, in-vitro culture,production of identical twins, andcloning.


Present and emerging technologiesthat build upon current embryotransfer procedures includepredetermination of sex, sexselection, in-vitro culture,production of identical twins, andcloning.

In addition, embryo transfertechniques proliferate a numberof new industries, such asresearch and growth ingonadotropin purification,manufacturing ofmicromanipulators and otherspecialized equipment,international marketing ofembryos, and specializedinvestment counseling.


In addition, embryo transfertechniques proliferate a numberof new industries, such asresearch and growth ingonadotropin purification,manufacturing ofmicromanipulators and otherspecialized equipment,international marketing ofembryos, and specializedinvestment counseling.

SummaryEmbryo transfer is a technologythat can be used to maximizethe production from superiorfemales.

Embryo transfer requires skill inthe management of reproductivecycles and skill in theperformance of the procedure.


Embryo transfer is a technologythat can be used to maximizethe production from superiorfemales.

Embryo transfer requires skill inthe management of reproductivecycles and skill in theperformance of the procedure.

ALL RIGHTS RESERVED

Reproduction or redistribution of all, orpart, of this presentation withoutwritten permission is prohibited.

Instructional Materials ServiceTexas A&M University

2588 TAMUSCollege Station, Texas 77843-2588

http://www-ims.tamu.edu

2007


ALL RIGHTS RESERVED

Reproduction or redistribution of all, orpart, of this presentation withoutwritten permission is prohibited.

Instructional Materials ServiceTexas A&M University

2588 TAMUSCollege Station, Texas 77843-2588

http://www-ims.tamu.edu

2007

Documents

EMBRYO TRANSFERstaff.unila.ac.id/gnugroho/files/2020/04/Embryo-Transfer-2.pdf · In cattle and horses, embryos for commercial purposes are usually recovered 6 to 9 days after estrus