Embryo TransferEmbryo Transfer

embryo is collected from a donor embryo is collected from a donor female and then transferred into a female and then transferred into a recipient female where the embryo recipient female where the embryo completes its development. completes its development.

Donor Female – must have Donor Female – must have outstanding genetics, be healthy, outstanding genetics, be healthy, and reproductively soundand reproductively sound

HistoryHistory

1890 – first embryo transfer done in 1890 – first embryo transfer done in rabbitsrabbits

1951 – first transfer in cattle1951 – first transfer in cattle profitable for producers of registered profitable for producers of registered

purebred animalspurebred animals done in cows, horses, goats, sheep, done in cows, horses, goats, sheep,

deer, elk, bison, wildcats, and camels deer, elk, bison, wildcats, and camels for racingfor racing

Superovulation:Superovulation:

refers to the release of many oocytes refers to the release of many oocytes (eggs) during a single estrus period(eggs) during a single estrus period

treat with gonadotropins (hormones treat with gonadotropins (hormones capable of promoting gonad growth capable of promoting gonad growth and functionand function

treat with FSH to induce the treat with FSH to induce the maturation and ovulation of a larger maturation and ovulation of a larger than normal number of oocytesthan normal number of oocytes

Superovulation one time – 0-20 Superovulation one time – 0-20 embryos with 7 normalembryos with 7 normal

Superovulation three times – 9-12 Superovulation three times – 9-12 calves normal calves normal

Non-superovulated cow – harvest a Non-superovulated cow – harvest a single ovum at every estrus = 5 single ovum at every estrus = 5 calves in one yearcalves in one year

** A mare does not respond to ** A mare does not respond to superovulation treatment**superovulation treatment**

Steps in Embryo Transfer:Steps in Embryo Transfer: Superovulation of donor with gonadotrophinsSuperovulation of donor with gonadotrophins AI (5 days after initiating superovulation) – inseminate AI (5 days after initiating superovulation) – inseminate

several timesseveral times Nonsurgical recovery of embryos (6-8 days after AI)Nonsurgical recovery of embryos (6-8 days after AI) Foley catheter for recovery of embryosFoley catheter for recovery of embryos Isolation and classification of embryosIsolation and classification of embryos Storage of embryos indefinitely in liquid nitrogen or at 37 Storage of embryos indefinitely in liquid nitrogen or at 37

degrees C or room temperature for 1 daydegrees C or room temperature for 1 day Transfer of embryos to recipients surgically or nonsurgicallyTransfer of embryos to recipients surgically or nonsurgically Pregnancy diagnosis by palpation through the rectal wall 1-Pregnancy diagnosis by palpation through the rectal wall 1-

3 months after embryo transfer3 months after embryo transfer Birth (9 months after embryo transfer)Birth (9 months after embryo transfer)

Non-surgical RecoveryNon-surgical Recovery

clean genital areaclean genital area give local anesthetic in rump and give local anesthetic in rump and

hiphip insert Foley catheter into vagina insert Foley catheter into vagina

and through cervixand through cervix fluid forced from the catheter into fluid forced from the catheter into

the uterus to flush out embryosthe uterus to flush out embryos fluid collected in a special containerfluid collected in a special container embryos filteredembryos filtered

Non-surgical Transfer:Non-surgical Transfer:

Embryos that pass inspection are Embryos that pass inspection are loaded into an AI strawloaded into an AI straw

Insemination rod is passed through Insemination rod is passed through the recipients cervix and into her the recipients cervix and into her uterusuterus

Embryo is expelled into the uterine Embryo is expelled into the uterine horn that is on the same side as the horn that is on the same side as the ovulated ovaryovulated ovary

Surgical Recovery:Surgical Recovery:

Unfertilized eggs must be collected Unfertilized eggs must be collected near ovulation (used in vitro near ovulation (used in vitro fertilization)fertilization)

Collected any time between Collected any time between fertilization and implantation (usually fertilization and implantation (usually after they migrate to the uterus)after they migrate to the uterus)

Usually done 6-9 days after estrusUsually done 6-9 days after estrus Method of choice in sheep, goats, Method of choice in sheep, goats,

and hogsand hogs

Surgical TransferSurgical Transfer

embryos in the early stages of embryos in the early stages of development must be deposited in development must be deposited in the oviductsthe oviducts

Conception rates 5% betterConception rates 5% better done by a midline laparotomy done by a midline laparotomy

(incision in abdominal wall) with (incision in abdominal wall) with general anesthesia OR through a general anesthesia OR through a flank incision with local anesthesiaflank incision with local anesthesia

Success Depends On:Success Depends On:

age and quality of embryosage and quality of embryos site of transfersite of transfer degree of estrus synchronization degree of estrus synchronization

between the donor and recipientsbetween the donor and recipients number of embryos transferrednumber of embryos transferred in vitro culture conditionsin vitro culture conditions skill of personnelskill of personnel management techniquesmanagement techniques