Justamom’s Blog

Since we started to sell some embryos I was asked some questions by prospective buyers that I for sure did not understand, so I started searching the internet trying to find an explaination that I  could understand in layman terms.   I hope is is informatitive for all. Please dont hesitate to add to it or hopefully learn as I did.  Alot of this is exactly as the article has worded it.   I was only gonna put a little bit out there at a time but it was too hard to follow that way so I know the article is large but hopefully informative for all.

Embryo transfer is one step in the process of removing one or more embryos from the reproductive tract of a donor female and transferring them to one or more recipient females.

 

1) Selection of the donor cow.

The first step is the selection of the donor cow. Beef

producers will differ in their opinions as to what is the

criteria for selecting a genetically outstanding cow. Whether

the criteria be performance records, showring appeal, or

both, consideration must be given to potential dollar value

of her calves.

 It has been suggested that

prospective donor cows in embryo transfer programs be

selected on the following criteria:

1) Regular heat cycles commencing at a young age.

2) A history of no more than two breedings per conception.

3) Previous calves were born at approximately 365 day

intervals.

4) No parturition difficulties or reproductive irregularities.

5) No conformational or detectable genetic defects.

She should be maintained at the level of nutrition appropriate

for her size and level of milk production.

 

2) Superovulation of the donor cow

“Superovulation” of the cow is the next step in the

embryo transfer process. Superovulation is the release of

multiple eggs at a single estrus. Cows or heifers that are

properly treated can release as many as 10 or more viable

egg cells during one estrus. Approximately 85 percent of all

normal fertile donors will respond to superovulation treatment

with an average of five transferable embryos. Some

cows are repeatedly treated at 60 day intervals with a slight

decrease in embryo numbers over time. The basic principle

of superovulation is to stimulate extensive follicular development

through the use of a hormone preparation given

intramuscularly or subcutaneously. The hormone preparation

will have follicle stimulating hormone (FSH) activity.

Commercially available preparations of FSH are injected

twice daily for four days, eight to 14 days following estrus,

while a functional corpus luteum (CL) is on the ovary. A

prostaglandin injection is given on the third day of the

treatment schedule, which will cause CL regression and a

heat or estrus to occur approximately 48 to 60 hours later.

 

 

 3) Insemination of the cow

Because of the release of many ova from the multiple

follicles on the ovaries over a period of several hours, there

is a greater than normal need to be certain that viable sperm

cells reach the oviducts of the superovulated females. Therefore,

many embryo transfer technicians will choose to

inseminate the cow several times during and after estrus.

One scheme that has been used successfully is to inseminate

the superovulated cow at 12, 24, and 36 hours after the onset

of standing heat. Using high quality semen with a high

percentage of normal, motile cells is a very critical step in

any embryo transfer program. The correct site for semen

placement is in the body of the uterus. Semen is placed

either in the body of the uterus or at the entrance into each

uterine horn.

 

4) Flushing the embryos

To collect the embryos non-surgically, a small synthetic

rubber catheter is inserted through the cervix of the

donor cow, and a special medium is flushed into and out of

the uterus to harvest the embryos seven or eight days after

estrus. This collection procedure is relatively simple and

can be completed in 30 minutes or less without harm to the

cow. The donor is given an epidural block and a presterilized

stylet is placed in the lumen of the catheter to offer

rigidity for passage through the cervix into the body of the

uterus. When the tip of the catheter is in the body of the

uterus, the cuff is slowly filled with approximately 2 ml of

normal saline. The catheter is then gently pulled so that the

cuff is seated into the internal os of the cervix. Additional

saline is then added to the cuff to completely seal the internal

os of the cervix. A Y-connector with inflow and outflow

tubes is attached to the catheter. A pair of forceps is attached

to each tube to regulate the flow of flushing fluid. The fluid

is sequentially added and removed by gravity. The fluid in

the uterus is agitated rectally, especially in the upper onethird

of the uterine horn. The uterus is finally filled with

medium to about the size of a 40 day pregnancy. One liter

of fluid is used per donor. Many operators use a smaller

volume and flush one uterine horn at a time. Each uterine

horn is filled and emptied five to 10 times with 30 to 200 ml

of fluid each time, according to size of the uterus. The

embryos are flushed out with this fluid into a large graduated

cylinder. After about 30 minutes, embryos settle and can be

located under a stereomicroscope by searching through an

aliquot from the bottom of the cylinder. Filters with a pore

size of 60 to 70 microns are also utilized to concentrate the

embryos.

5) Evaluation of the embryos

As the individual embryos are located using the microscope,

they are evaluated for their quality and classified

numerically as to the potential likelihood of success if

transferred to a recipient female. The major criteria for

evaluation include:

Regularity of shape of the embryo

Using these subjective criteria embryos are classified as:

Grade 1: Excellent or Good

Grade 2: Fair

Grade 3: Poor

Grade 4: Dead or degenerating

To maximize embryo survival in the recipient female

following transfer, conditions in the recipient reproductive

tract should closely resemble those in the donor. This

requires synchronization of the estrus cycles between the

donor and the recipients, optimally within one day of each

other. Synchronization of the recipients can be done in a

similar manner and at nearly the same working time as the

donor cows. Injectable prostaglandin products are available

from veterinarians and should be injected 12 hours prior to

the injection of the donor cow. This should optimize the

probability that the recipient would be in the same stage of

the estrus cycle as the donor when transfer takes place. Use

of the “Syncro-Mate-B” system which involves injecting

the recipients and implanting them with a synthetic progesterone

also has been used successfully. The implant is

removed nine days after its insertion, and the cows will show

standing estrus approximately 30 to 40 hours later. Again,

this timing must match the time of estrus of the donor cow

so that the donor and the recipients have a similar uterine

environment seven days later when the transfer takes place.

Remember synchronizing drugs only are effective on recipient

females that are already cycling. “Anestrus” or noncycling

cows that are too thin or too short in postpartum days

will not make useful recipients.

Heat detection is exceptionally important. Recipients

should be properly identified, observed for heat 2 to 3 times

daily, and adequate records made of date and time of estrus.

7) Transfer of the embryos

The transfer of the embryo into the recipient cow first

requires “loading” of the embryo into a 1/4 ml insemination

straw. This is done under microscopic viewing with the aid

of a 1 ml syringe and requires considerable practice, patience,

and dexterity. Degenerated embryos or embryos of

very low grade need not be loaded and can be discarded. Just

prior to embryo transfer, an epidural anesthetic is given, and

the ovaries of the recipient are palpated rectally to determine

which ovary has ovulated. With the aid of an assistant

to hold open the vulva of the recipient cow, the transfer gun

or insemination rod is carefully passed through the cervix.

The tip of the rod is then guided into the horn on the same

side of the ovary with an active corpus luteum. The embryo

is gently expelled in the forward tip of that uterine horn.

Great care is taken to not cause damage to the lining of the

uterus. Such inflammation and scarring would greatly

reduce the probability of the pregnancy being established.

Embryos can be transferred immediately upon recovery

and evaluation, or may be stored frozen in liquid

nitrogen and transferred at a later date. The freezing andthawing process also is very intricate and usually results in

an approximate 20 percent reduction in pregnancy rates

from those observed with fresh embryos.

Frozen embryos are a marketable commodity and have

especially been useful in international sales of United States

beef and dairy genetics. Producers in this country that

believe that they own cattle with the genetic capability to be

valuable in other nations may wish to contact their state

department of agriculture and ask about regulations and

marketability of frozen embryos from their herd. Different

nations have different health requirements of cattle producing

frozen embryos for import into their country. Therefore,

individual inquiries are necessary to learn what health and

legal requirements are expected

 

 

 

 

 

Getting around to the computer again, Im having a ton of computer trouble now so Im frusrated to the ends of the earth.  After going to the Iowa Beef Expo on Sunday I was super impressed with the quality of cattle being presented there.  Some of the classes had 16-20 or more in a class and they were 10 or more calves deep that could have been switched up either way, the steer classes were especially deep as well as the commercial heifer classes.  It is obvious to see that everyone is learning how to groom and present their calves better than ever, and Wow what a crowd.  We are are blessed to live here in Iowa and witness the quality of the cattle and the wonderful kids that we are raising here in Iowa,  its truely a great thing to see.  I didnt see any kids behave anything other than professional in the ring.  I am wondering however how all these people are affording such animals, Im pretty sure that if you took the top five or six in some of the crossbred steer classes or commerical classes there you would be topping the six figure mark,  I wonder how everyone explains that to their banker that this is what they are paying for these cattle???  I know some are winning big money but thats usualy only one kid the rest all take the same trip to the packer as the cheap steers.  I can understand somewhat the prices of the heifers as they are producing cattle but steers……   I also felt it was the least political Beef expo I have witnessed as I saw alot of different class winners, it was nice to see and a testimate that people are getting smarter at picking out calves and possibly raising their own.

With embroys available I feel it levels the playing field some.

It was great to see old friends that I only see once or twice a year and catch up, this is a social event for me so I really enjoyed my self.  Good kids, good people, good cattle what else would a gal want.

Guess we all have blogs now- Oh happy day- I guess Id like to try and dig up some of my old 4-H stuff the kids had and add some ideas, suggestions, and all that jazz for you and your kids to use, both boys were pretty successful and were blessed to have good 4-H leaders that cared and encouraged each and every child in the club.  Also though Id talk about how we run our fair Im on the beef committee, have been for about 15 years, and how things have changed.  And of course Ill talk about some of my favorite things, my kids, my family and cooking.

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