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Embry Transfer is increasingly being used for various reasons. These include
  1. Embryo Transfer allows mares to produce foals from as young as two (2) years of age while continuing to perform.
  2. Embryo Transfer allows production of foals from older sub-fertile or unsound mares or mares with a history of pregnancy loss (resorption or abortion). In reality these mares are not ideal donors, as embryo recovery can be as low as 20% per cycle.
  3. Embryo Transfer allows production of more than one foal per mare per year. It is feasible for mares to produce up to six (6) foals in a season.

With such a limited amount of Gypsy Horses in Australia ET is an attractive procedure for getting quicker returns from your investment or to simply increase the breeding population available in Australia. However done irresponsibly it will further reduce our gene pool rather than help the breed. There are also some farms in the US now that seem to be producing "litters" of embryo foals for the quick dollar rather than making a few superior embryo foals available.

There is no doubt ET is a very useful tool and I am certainly not against it. However I would like to see some controls put in place to combat what is often called Embryo Abuse.

I honestly can't remember where I got this article, off the net somewhere. But it is a good article explaining ET, problems and otherwise. I've added a bit about super ovulating mares below it, plus a short article on Cloning. Proof of the strange new world we live in.

Embryo Transfer -- recovering the embryo from a bred donor mare for placement into a recipient mare to carry and raise the foal--has become a very useful reproductive tool for a growing number of breeders in breed registries that approve it. Many breeds now allow registry of foals produced through ET (embryo transfer), including the Quarter Horse, Paint Horse, Arabian, Appaloosa, Peruvian Paso, several of the draft horse breeds and warmbloods.

The American Sporthorse was one of the first organizations to promote ET in horses, in the early 1980’s. Their research money helped make Colorado State University (where much of the early work was done) one of the foremost facilities for equine ET.

Some breed registries have restrictions about how many foals can be registered per year from the same donor mare, while others accept unlimited registrations. The AQHA, for instance, only allowed one foal per mare to be registered annually but recently relaxed this rule, due to pressure from members. Now that more of the foals can be registred with AQHA, this has opened more doors from a research standpoint. Even for the breeder that doesn’t use ET, we can all benefit indirectly from what we learn (about equine reproduction) by doing it.

History of equine ET -The person doing embryo transfers the longest in the United States is Stephen Vogelsang, now doing reproductive work at Wichita Ranch at Brenham, Texas, where he has worked for 11 years. He became interested in embryo transfer while in graduate school at Texas A&M, and did the first equine embryo transfer in 1977. “I had been exposed to ET work in cattle, and didn’t see why we couldn’t do this in horses. I worked with Dr. Duane Kraemer, a professor at Texas A&M who was a pioneer in ET work. He had just finished doing the first ET in primates. We didn’t see any reason we couldn’t do it in horses--if we could get the research animals together, which I was able to do," says Vogelsang.

“I got an embryo out of the first mare we did, and that first transfer resulted in the first ET pregnancy in horses in the U.S. in 1977. This had been done already in England and Japan, so that made ours the third one in the world. At that time, people felt ET would not be accepted by the horse industry--that it would be a technique just used for research,” he says.

“The first ET foal (“Miss T”) we produced at Texas A&M in 1978, we submitted for registration in the AQHA, and they would not accept it because there was another foal born that same year from the donor mare. But AQHA set up guidelines for ET, and decided to accept this technique on a limited basis. At that point, they only let us do it in mares over 15 years-old or barren for 3 or more consecutive years. We functioned under those requirements until 1988 when the rules were changed to allow ET on any mare,” he says.

“After I finished at Texas A&M, I worked for Quarter Horse breeder Jack Benson, from 1978 to 1980, at Stallions Unlimited in Brenham, Texas. We stood The Investor. Then I went to work for Sam Wilson in Pattison, Texas who stood Skip A Star and Son of a Doc, and a few lesser known Quarter Horse stallions. While I was there (1981-1983), I bred 500 to 600 mares a year.” In 1984, he went to work at Granada Equine Service, and was with that company for 10 years.

“Granada was, at that point, the largest company involved with ET in cattle in this country. At one time they were doing 10,000 ET pregnancies a year in cows. With the technical support I had there, we started doing commercial ET in horses,” says Vogelsang.
While he was with Granada he had a lot of support personel for ET work with horses. “The people doing cattle ET helped adapt some of those techniques for use in horses. In cattle, they were also involved in the initial work with cloning, dividing embryos, freezing embryos, and in vitro fertilization,” says Vogelsang.

Why Use ET? - Embryo transfer is a way to get foals from a problem mare that cannot carry a pregnancy, or to extend the reproductive life of an older mare, a way to raise foals from a mare while she continues a performance career, and a way to “back up” a mare that foals late in the season, without losing a year of reproduction. Some breeders use ET to get more than one foal a year from a mare.

It’s also good insurance. There have been cases in which a young mare dies during her showing career, yet she had an embryo being carried by a recipient mare, and thus had one more foal after she died. Use of ET allows mares to have a double career; they don’t have to take time out to have a foal.

“Probably the main reasons people do it is so they can keep showing the mare, or to get foals from her by multiple stallions,” says Vogelsang. “People book mares to more than one stallion, and breeding contracts today address this issue, as to which stallion the mare will be bred to first, at what stage she will be bred to the second stallion, etc. For instance, in our contract for Mecom Blue, it states that he’s the first stallion that the embryo is produced by, and the mare won’t be changed to another stallion until we actually develop a viable pregnancy. Otherwise, you get into a situation where you have multiple stallions involved and if there’s a hang-up along the way, then you have multiple returns.”

ET is a good tool to find out what stallion a mare crosses best with. You can get some foals on the ground and get them trained, rather than having to wait until she retires from a performance career to finally figure it out. You may know her best cross by the time she’s 7 or 8, and can raise quite a few more, if the stallion is still alive.

Vogelsang says, “Due to AQHA restrictions, we started, at first, just doing problem mares and old mares. We thought it would be a panacea for the problem mare. We subsequently found out that a lot of those mares, because of their age or inherent problems, still had a low success rate with ET.”

He thinks this is due to the fact that an embryo from the old mare has less quality than embryos from young mares. “The old mare has a low reproductive success rate because of other factors besides an old uterus with senile changes and scarring. Even though you take her embryo and put it into a young, healthy uterus, you may not always be successful. The embryo from the old mare is just not as viable as that from a younger mare,” he explains.

“In looking at comparisons with other species, you find that in the older human female, such as a woman over 40, there are some genetic problems you are more concerned about than in the younger woman. There’s a lot more risk, and it’s not just the uterus, but also with the oocyte itself. Remember that all those eggs are what she was born with--the eggs she has throughout her life. The female is not reproducing eggs like a male is reproducing sperm; all her eggs have been there from the beginning,” he says.

“If you take a mare that’s 20 years-old or so, those eggs you are dealing with are 20 years-old. When you look at the pregnancy rate with old mares, you’ll end up with--even with good management--about a 10 to 15 percent lower success rate, compared with normal, healthy young mares,” he explains.

The breeding contract usually entitles you to a single offspring from a stallion, and additional offspring produced (as with multiple embryos from that breeding) would require secondary fees. “A second pregancy (as when the mare has twin embryos) is usually a new deal, and you pay an additional stud fee for that pregnancy; it comes under a separate contract. Most stallion owners are okay with that, and it’s important for us (the technicians doing the collection) to be up front with stallion owners, to let them know what has occurred, especially in the case of shipped semen. We let stallion owners know there are additional embryos, so they are aware there’s a possibility for additional stud fees,” says Vogelsang.
“The contracts may vary on this, depending on the stallion owner. In our contract, the second stud fee is due once we have the second pregnancy. After it gets to a viable stage at 45 days or so, the second fee is due at that point. There might be some owners who require a secondary booking fee before you make the second transfer. There may be some variation in how the fee is handled,” he explains.

He started downplaying ET work for problem mares and putting more emphasis on using young mares that are still performing and at the peak of athletic careers--at the height of their popularity. “It made more financial sense to work with that young mare, just as a stallion is most used when he’s young, popular and winning. We needed to take the same attitude toward mares, since at this point in their lives and careers their foals are worth the most. They will be more in demand when the mare is winning than they will when she’s older and out of the limelight. You can get some ET foals from her while she continues to perform,” he says.

“This idea started catching on in the mid-1980s, once we broke down that barrier of people thinking that an ET foal might be inferior to a natural foal because it didn’t have its own mother raising it--especially after ET foals started winning at cutting. Then it almost became faddish, with cutting horses, to go that direction. It makes a lot of sense with the young mare; if she’s able to win $20,000 or more a year she can more than justify doing ET and producing a foal that will be in demand when she’s at the height of her popularity. Doing ET with young mares has now surpassed use of ET in problem mares and older mares as the number one reason why we do it,” he says.

“Another reason (to use ET) is with an old or debilitated mare that has a physical problem such as founder or a torn cervix or anything that prevents her from carrying a pregnancy to term. A fourth reason would be to move a mare earlier in the season if she's foaling late. You can leave her open and breed her earlier the next year, and yet not miss a year of production, since a recipient mare can carry a foal for her.” Now a fast-growing reason for using ET is to produce more than one foal a year from a certain mare.

Costs of ET Services - The cost of doing ET is anywhere from $2000 to $5000, and this includes the recipient mare as part of the package. “A lot of people will charge a $1000 deposit, which includes a number of embryo collections. I charge a $300 collection fee for each embryo collection. That way if somebody does one collection or two collections and we’ve not had any success and they want to quit at that point, they still have that option. We also emphasize that the $2000 to $5000 for the ET does not include the stud fee for the stallion used; it’s just for the ET service,” he explains.

Costs have come down from what they were in the beginning. “There are some labs that are doing it cheaper than others, but you need to do your homework and know exactly what you are paying for. With the cheaper ones, the mare owner is usually incurring the risk regarding the recipient mare. If something happens to her, it’s your responsibility. In other contracts, you have some guarantees involved. Some facilities have more track record and you may have more chance for success.” You basically get what you pay for.

Factors That Affect the Success Rate - “The main factors that affect success with ET are the donor mare herself, the quality of the recipient mare, the overall quality of the embryo, and season of the year. The mare herself is the first factor--whether she’s an old mare with a problem (like chronic founder), and in a lot of pain; that’s not a positive situation as far as trying to get her pregnant. For ET work, she has to get pregnant first. Along the same line, if you are dealing with a 25 year-old mare that hasn’t had a foal for 3 or 4 years, you’re toward the end of the game with her; you’d have to be very lucky,” he says. This is why most of the ET work today is concentrated around the young mares.

Some of the mares that are hard to get embryos from are mares that are chronically infected, and old mares that accumulate a lot of fluid in the uterus. A mare that just has degenerative changes, with no concurrent infection or fluid buildup, will furnish embryos though recovery rate will be lower. These are usually older mares, and there are some other senility changes that go along with this condition. They may have transport problems (getting a fertilized egg to the uterus) in the oviduct, or fibrosis (scarring) that interferes with passage of the egg.

“The next factor that affects success is the recipient mare,” says Vogelsang. “That’s one reason we use our own recips (rather than a mare provided by the client) because we have more history on them. Reproductive health of a recipient mare is very important. This is probably the most critical thing, regarding the success of the transfer, because that’s where the embryo is going,” he says.

The third factor is the quality of the embryo removed, which in many ways also comes under the first category (age of the mare). “Regarding age of the embryo, the older it is, the more risk for failure. We primarily deal with 6 to 7 day embryos. When you get past day 8, you are dealing with an embryo that’s relatively large and easy to damage. Age of the embryo will be controlled by how accurate your detection methods are. This has improved immensely over the years with the way we utilize ultrasound compared with just palpation,” says Vogelsang.

Time of year can be a factor (you want it to be at the optimum time, reproductively, for the mares), and even the stallion is important, regarding the survivability of the embryo. “In cattle work, there are embryos by certain bulls that have much higher success rate than those from other bulls, and the same is true with horses. Some stallions I’ve worked with produce very hardy embryos, while some others are more fragile,” he explains.

Multiple Ovulations - “A common question is whether we can get more than one egg at once, like we do in cattle. In horses, it's been mostly single egg collection until recently. Most of the super-ovulation products for horses were still experimental until a few years ago. A lot of people are doing it now, but I want a little more research data before I start doing it on a large scale. Most of the mares people want this done with are high dollar mares, so I’ve been a bit conservative up to this point,” he says.

There are a growing number of commercial facilities that offer ET services and furnish surrogate mothers (recipient mares). They contract with mare owners for the transplant service. The mare is bred to a stallion of their choice (using shipped semen or taking them to a breeding farm) and brought to the facility to have the embryo flushed out and transferred into a recipient mare. There’s also a lot more shipment of embryos around the country today. Wichita Ranch ships almost all the embryos to other facilities for transfer into outside recipients. Then the recipients are not competing with breeding mares for space or personal time. Work at the university level is minimal today; most embryo work is now done by commercial facilities.

“There's a tremendous amount of individual variation on success rate. You’ll have some mares, depending on how they build follicles, that will respond very positively. When you stimulate a mare to super-ovulate, you might have 3 or 4 ovulations or, in extreme cases, maybe 6. In most cases you’ll get 3 ovulations on average. And there’s a significant percentage of mares in which you won’t get a response to the drug. The cost will range from about $300 to $400 for the treatment, and it may not work.”
He is still “on the fence” regarding superovulation. “I feel that you may overstimulate a mare, to where it may actually set her back and she won’t cycle back for a period like you’d expect. In cases where people want foals from multiple stallions, this doesn’t help. I have a number of mares this year that will go to several different stallions, so you don’t want to mess that up. I’m still waiting and watching on the use of superovulation. I will be doing some this year, but not a lot,” says Vogelsang.

“You can follow and map those mares over multiple cycles, and with experience you’ll be able to tell whether a mare will respond well to the drug--which ones will be a good risk for this technique and which ones won’t.” You can get to know the mare, to determine which ones to gamble on and which ones would be a waste of money.

Double ovulation in the mare occurs naturally about 10 to 15 percent of the time (twins). Some mares have double ovulations more consistently than that, and work out very well as donors because there is no problem transferring both eggs. Many mares double ovulate, but under natural conditions few twin pregnancies go full term. Mares have a way of reducing the extra embryo themselves. By the time most people know a mare is pregnant, there’s usually only one fetus. “Your possibility of transfer success with a twin is just as good as a single. I usually have at least one set of twins born per year, carried in different recipients.”

Reducing the Drawbacks of ET - “The downside of using ET is that it’s a reproductive insult to the donor mare. We must keep this in mind in terms of how many times we do it with her. At one point during the early years of ET, we felt flushing a mare’s embryos had no effect on her future fertility, but it can, if you overdo it. You must realize that when we do ET collection there’s always the possibility of contamination and infection. You’re going through a closed cervix (the mare is out of heat by the time you collect the embryo), so you must dilate the cervix, possibly causing a small amount of irritation. If you do it too much, I suspect this could result in adhesions. This problem with the cervix could also be the result of mares not carrying foals naturally.”

“In those mares, even if you have a little damage in the cervix, by letting them go through a normal pregnancy it seems like the pregnancy restores the normal integrity of that cervix. When the mare goes through a normal foaling process, it’s a natural way for the cervix to re-establish itself. Pregnancy shuts the uterus down for awhile (no continual cycling); the mare goes through 11 months in which the uterus is closed off from the outside, and this gives it a chance to restore itself. This is my theory, but it seems to be a factor,” Vogelsang says.

“I’ve had some mares that you can do 2 embryo collections and you’ll notice they have a lot of inflammation. So you need to back off, give the mare more time, skip a cycle. Then you can come back and do it again. You can’t just keep flushing her or you’ll get to the point where you can’t recover embryos from her at all.”

A technique developed for problem mares, called GIFT (gamete intrafallopian transfer), involves recovering the unfertilized egg from a mare’s ovary, putting it into the oviduct of a recipient mare, then breeding the recipient mare--having it fertilized in the recipient mare. This is more complicated and expensive than ET, but can work sometimes to get a foal from a mare with fertilization and transport problems (getting the fertilized egg from the ovary to the uterus where it can be collected) or degenerative changes that prevent her from becoming pregnant.

Recipent mares - Vogelsang says the main criteria for a recipient mare is that she be reproductively healthy, with adequate pelvic area; it doesn’t matter what breed or size she is, if she’s an easy foaler. “There was research done in Europe where they put embryos from normal size horses into pony mares. Those foals were smaller at birth from the pony recipient mares, but by the time they were of weaning age they’d caught up and were no different in size.”

The best recipients are usually about 5 to 7 years-old. This is the easiest age group to get pregnant. “They also need good vulva conformation (vertical). If a mare has a sunken anus, she’s more prone to develop infection. I don’t want a mare that needs a Caslick’s; I don’t want one that makes more work for me,” he says.

“With embryo transfer, your success can hinge on a number of factors. The first critical part, of course, is actual recovery of the embryo, and that can vary, depending on whether you are dealing with cooled or frozen semen, or semen from an average stallion or a sub-fertile stallion. All these things can have an effect on whether you get an embryo.
Normally you should be able to expect, on your average, healthy mares, an 85 percent or higher recovery rate if everything is working right,” says Vogelsang.

Recipient mares need not be big. Some people think a draft mare would be best, but as a general rule draft mares are not as dependable reproductively. There’s also more feed and upkeep with a big mare. Many recipients are Quarter Horse or Quarter Horse type, Thoroughbreds or Appaloosas. Many people doing ET work specify the need for “roomy” recipient mares, but Vogelsang points out this does not mean size of the mare, but rather her pelvic area. “I've seen some Thoroughbred mares that had quite a bit of size, but they were small through the pelvis. Those kind of mares are not a good choice for recipients, and you’ll discover this problem when you palpate them. Just as in cows, pelvic area is more important (for easy birth) than is the size of the mare. I’ve had Arabian recipient mares that carry Quarter Horse foals very nicely. We tend to think the Arabian is too small, but if you have one that’s adequate through her pelvis, it’s no problem,” he says.

“The main thing about a recipient mare is that she be healthy and reasonable to work with. When I purchase a recipient mare, I like to get one 4 to 8 years of age, and a good recipient mare will stay in our herd until she’s 12 to 14, if she’s still coming back to us at that point. The way our fee structure is, we give a deposit back on the recipient, to try to get those mares back to us. I probably have a few now that are 15 to 16 years-old, but they are sold if they start to have any kind of problem.”

Freezing Embryos - Some people are freezing embryos so they can be stored or shipped and put into a recipient mare at a later date. “Success rate was low at first. When I was working with this at Granada, we had some international clients interested in buying embryos. But at that time the embryos from really good mares were too valuable to freeze, because of the risk involved (only a 30 to 40 percent success rate). Now the success rate is more like 60 to 70 percent,” he says.

Today there’s a lot more interest in freezing embryos, partly for international trade, or for collecting them at different times of year and then transferring them at a more opportune time. “For instance, we can freeze an embryo in November and then transfer it in March. If a mare has a heavy show schedule in the spring, we can collect it in the fall and save it for a more reasonable time.”
“Once you have the embryo, other factors enter in. The ET collection technique is pretty simple--basically lavaging the mare’s uterus and filtering out the tiny embryo, which will range from 200 microns in size up to as large as 2 millimeters, which is getting up to the risky size. I have produced pregnancies from embryos that barely fit into the tip of an insemination pipette, which is probably close to 3 millimeters, but that’s too big.”

ET success (after the embryo is collected and prepared) will range anywhere from 50 to 70 percent on old mares, to more than 85 percent on young, healthy mares. “Some people will quote figures of 90 percent. If you include all the numbers, including embryos that are shipped out, our facility had over an 85 percent success rate last year, and much of that comes down to good management of recipient mares. This includes management of the recipient at the commercial facilities that we ship embryos to. We’ve all gotten better at managing the mares,” he says. The overall success rate for ET has improved about 20 percent over the past 10 years.

The Process - The flushing of the donor mare (to recover the embryo) must take place 6 to 9 days after the mare ovulates. A catheter is placed through the mare’s cervix, to carry the fluid. There are two passageways in the catheter. One carries the fluid and the other puts air through, with a cuff at the end that blows up like a tiny donut. It is inflated once you get it into the uterus, and it acts as a plug to keep the fluid from coming out. It also keeps the catheter from falling out while you are flushing the mare. A liter of buffered saline flows into the uterus.

This solution is warmed to body temperature first by putting it into a water bath for an hour. Technicians may add calf serum or bovine serum albumin to help with viability of the embryo. Embryos tend to be sticky, and this also coats the tubing and glassware so the embryo won’t stick to the tube. After the liter of fluid goes into the mare’s uterus, flowing in by gravity, it is allowed to drain back out.

On its way out, it goes through an embryo filter which is a little cup with a screen mesh in it. The pores in the filter are smaller than the embryo to catch it. You may see the embryo in that first liter of fluid you recover from the mare. If you don’t find it in that liter, you must run in another fresh liter, or even a third or fourth liter. Most of the time, the embryo will be in the first liter. Flushing the mare takes about 15 minutes, then the fluid is taken into the lab to find the embryo.

Age of the embryo and suitability for transfer is evaluated, then it’s transferred into the recipient mare (going through the cervix and depositing it into her uterus). Day 8 is ideal for flushing, since this is the easiest day (embryo size), for ease of handling and transfer. Six days post-ovulation is the earliest you can flush a mare and recover the embryo because there’s a certain amount of transport time. It takes about 5 days for the embryo to travel down the fallopian tube; you can’t retrieve it until it comes down into the uterus.

When flushing the donor mare, the process is simple. There’s actually more risk involved for the recipient mare since she’s not in heat, and more prone to pick up infection since the technician must open her cervix. The recipient mare must be near the same point in her estrus cycle as the donor mare, so her uterus will be prepared to receive and nourish the embryo. When selecting a recipient mare for a transplant, you match the recipient with the donor mare. The donor mare, at day 6 to 9 post-ovulation, is now out of heat, and so is the recipient mare.

If you’re going to ship an embryo, the procedure is similar, except that in the last step the embryo goes into a different kind of media, and you also have to cool it. A salt solution is always used as the flushing agent. The embryo will be fine in this for two to three hours, but after that it needs to be in a culture medium, that it can actually grow in. In this environment, it can be packaged and shipped, or taken to put into a mare somewhere else.

With ultrasound, a person can tell if the embryo took by the time it is 11 to 12 days old--which will be only a few days after you’ve transferred it. You can see 90 percent of the embryos by the time they are 11 days old, and 95 percent of them by day 12. If it’s not visible by 14 days, it probably didn’t take.

The Equine Embryo - At its earliest stage, the embryo is very tiny but also very tough. The 8 day old embryo is more fragile; the bigger they get, the more fragile they become. The only ones you can safely freeze are those at day 6. Once they get to day 7, you can cool them but you can’t freeze them; there’s more fluid in the cells by then and freezing and thawing would rupture something.

The 7 day-old embryo is about the size of the ball on a fine-tipped ball point pen. The 8 day old embryo is about .9 to 1.5 millimeters in size, the 9 day-old embryo is 2 to 3 millimeters, and the 10 day-old embryo is 3 to 5 millimeters in diameter--very easy to see. The early stage embryo doubles in size from day to day until about day 15 or 16 days, which makes it easy to see on ultrasound any time after day 10. Mares’ embryos tend to be spherical, and the 7 day-old embryo has the texture and appearance of a semi-transparent golf ball, with a smooth capsule on the outer surface.

Embryo Transfer is the wave of the future of breeding, however, the challenges presented by Mother Nature provide a natural check to the reproduction process.

SuperOvulating Mares - For your InTEREST only, not available in Australia

Fertility in the mare begins with ovulation. The mare naturally ovulates one ovum (egg) per 21-day cycle. In a typical breeding season, February through July, this presents six to eight opportunities for ova to be fertilized. Compared to the mare's spontaneous (unassisted) ovulation, superovulation maximizes the fertilization opportunities by inducing the development and ovulation of a greater number of follicles. This method can optimize fertility--ova mature in follicles, so a greater number of follicles means more oocytes and an increased likelihood of conceiving more foals.

Superovulation maximizes the fertilization opportunities by inducing the development and ovulation

of a greater number of follicles.

With a higher probability of establishing a pregnancy, superovulation might result in the fertilization of multiple oocytes. This gives us a possible opportunity to collect more than one embryo for implanting into donor mares via embryo transfer.

Superovulation stimulates the entire follicular wave. Those follicles that might have degenerated--or not have been selected to ovulate--will go ahead and ovulate in addition to the dominant follicle.

Equine pituitary extract (EPE) has succeeded in producing multiple ovulations. This preparation consists of gonadotropins from the horse's pituitary gland. At CSU, gonadotropins are extracted and processed to yield the EPE compound. McCue defined the resulting EPE as containing "approximately 6-10% LH (luteinizing hormone) and 2-4% FSH."

He described the use of EPE to superovulate mares at CSU.

"The exact day of ovulation is determined and the mares are then short-cycled with prostaglandin (PGF2alpha) five days later and administered 30 mg. of EPE as an intramuscular injection once daily." Prostaglandin destroys the corpus luteum, and it starts the estrous cycle just prior to the beginning of the next follicular wave. EPE treatment lasts approximately six to eight days.

"When multiple follicles greater than 35 mm in diameter are detected, the mares receive 2500 IU human chorionic gonadotropin (hCG) intravenously to promote synchronous ovulations," said McCue. A mare is bred prior to ovulation and also when she ovulates, immediately after researchers detect ovulation.

Recent research has shown that EPE provides better multiple ovulation results than other hormone treatments. For example, researchers have studied the effects of gonadotropin-releasing hormone (GnRH), which helped improve ovulation rates through multiple ovulations in seasonally non-cycling mares. However, this hormone showed less-promising results on cycling mares.

At CSU, the results of superovulating 55 mares in the embryo transfer program in the 1994 and 1995 breeding seasons were an overall 2.4 ovulations per cycle, with a range from one to five. Of mares treated with EPE, 74% had multiple ovulations. Researchers elsewhere had reported as many as 10 ovulations in one mare due to EPE treatment.

Mares were bred with either shipped cooled semen or frozen-thawed semen, and pregnancies monitored with ultrasound. Results were double the number of embryos collected per donor (from the superovulated mares as compared to non-treated mares).

Other studies at CSU have investigated whether superovulating normal mares can lead to increased pregnancy rates in mares bred to a subfertile stallion. McCue noted that mares ovulating multiple follicles had a 67% pregnancy rate, compared with 33% for the mares with a single follicle. This result was for mares inseminated with a limited dose of frozen semen.

Cloning is Here to Stay!

The combined efforts of animal cloning leader ViaGen Inc. of Austin, TX and performance horse marketing experts Encore Genetics Ltd. (Weatherford, TX, USA) is set to present as many as 30 (thirty) cloned foals next year with foalings starting in February. The DNA source for the clones is described as being "six high-profile performance horses". Breed and discipline are at this time unannounced, although it has been reported that they are not of the Thoroughbred breed, the Registry for which remains resistant to anything but live cover techniques, regardless of the safety of animals and personnel. Royal Vista Southwest has provided the recipient mares for the process, and it is in Purcell Oklahoma that the foals will begin to be born next (2006) spring.

Just to add to the "clone melting pot", in a different project, it appears that there are a projected 9 (nine) clones of the Quarter Horse stallion Smart Little Lena due to be foaled next year at Texas A&M University (College Station, TX, USA). As we noted above, cloning equines is definitely here to stay, and we are glad to see pro-activity in the Registry world with Zangersheide leading the way in issuing registration documents. If this were to be coupled with micro-chipping, we suspect that it would go a long way to avoiding confusion and mix-ups once the clones themselves start to reproduce. It would seem logical to issue a Registration document with the same number as the originating DNA animal, plus a suffix indicating a clone. For example, with Smart Little Lena one might see clones identified with the Registration numbers 1565822(a); 1565822(b); 1565822(c) etc. Such an identification is going to be necessary, as once the male offspring have become sexually mature, any offspring produced by a clone will have identical DNA to an animal produced by the original cloned animal. This means that semen collected, frozen and subsequently used to breed mares cannot be differentiated from semen from the original stallion that was cloned. It would seem therefore essential that some form of "paper trail" be developed before too many cloned colts reach sexual maturity! Pro active would seem to be the way to be, not re active! We will be interested to see what AQHA's response is, but at the moment it does not look promising - AQHA rule 227 specifically states:

          (a)Horses produced by any cloning process are not eligible for
          registration. Cloning is defined as any method by which the genetic
          material of an unfertilized egg or an embryo is removed, replaced by
          genetic material taken from another organism, added to with genetic
          material from another organism, or otherwise modified by any means
          in order to produce a live foal.

The only trouble with this is that any offspring of a clone produced by normal breeding methods is not going to be eligible for registration, as a result of the sire or dam having been ineligible - even though clones are just "twins separated in time". It's going to be interesting...!

CLONING - Another Gelding to Breed!

In 1985 a plucky gelding and an even pluckier 15 year-old lady ran into the record books and the hearts of the American barrel-racing public. The gelding was a quarter horse called "Gills Bay Boy" - better known as "Scamper" - and the young lady was Charmayne James. Their amazing feat was winning the heat at the NFR for the barrel racing finals in 14.40 seconds - despite having no bridle in place - the bridle had broken during the run! Scamper and James went on to win the World Championship that year - being the second year for them to do so; another amazing feat being that James was only 14 years old when she won her first World Championship with Scamper - and for another 8 more years to follow!

Now, after both James and Scamper have retired from major competitions, they are once again making history! Scamper is undoubtedly the bearer of superior genetic performance material. As a gelding there has not been a way until recently for that genetic material to be passed on to the next generation. Scamper has been cloned! This means that the clone - named "Clayton" after James' childhood home where she and Scamper first met - once sexually mature, will have the potential to pass on those superior racing genes.
ViaGen Inc. of Austin, TX and Charmaine James were today (11/15/06) pleased to present Clayton to the public for the first time.

This once again raises the question of whether the AQHA will develop some sort of registration and recordation system for cloned quarter horses and their offspring. It is unlikely that the cloning process is going to cease, and it seems regrettable that superior genetics such as "Scamper" should be witheld from American Quarter Horse breeders wishing to improve the quality of their own stock and that of the breed as a whole! Charmayne James in addressing our question on this topic at the news conference seemed positive that the issue will certainly be reviewed.

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