Editing Horse breeding (section)

=== Advanced reproductive techniques ===
[[File:Andrew Thornton.jpg|thumb|upright|right|The [[Thoroughbred]] industry does not allow AI or embryo transplant.]]

Often an owner does not want to take a valuable competition mare out of training to carry a foal. This presents a problem, as the mare will usually be quite old by the time she is retired from her competitive career, at which time it is more difficult to impregnate her. Other times, a mare may have physical problems that prevent or discourage breeding. However, there are now several options for breeding these mares. These options also allow a mare to produce multiple foals each breeding season, instead of the usual one. Therefore, mares may have an even greater value for breeding.
* '''[[Embryo transfer]]''': This relatively new method involves flushing out the mare's fertilized embryo a few days following insemination, and transferring to a surrogate mare, which has been synchronized to be in the same phase of the estrous cycle as the donor mare.<ref>[http://www.aaep.org/health_articles_view.php?id=143 "Embryo Transfer"] {{webarchive|url=https://web.archive.org/web/20080415220448/http://www.aaep.org/health_articles_view.php?id=143 |date=2008-04-15 }}</ref>
* '''Gamete intrafallopian transfer (GIFT)''': The mare's ovum and the stallion's sperm are deposited in the oviduct of a surrogate dam. This technique is very useful for subfertile stallions, as fewer sperm are needed, so a stallion with a low sperm count can still successfully breed.
* '''Egg transfer''': An [[oocyte]] is removed from the mare's follicle and transferred into the oviduct of the recipient mare, who is then bred. This is best for mares with physical problems, such as an obstructed oviduct, that prevent breeding.
* '''Intracytoplasmic sperm injection (ICSI)''': Used in horses due to lack of successful co-incubation of female and male gametes in simple IVF. A plug of the [[zona pellucida]] is removed and a single sperm cell is injected into the ooplasm of the mature oocyte. An advantage of ICSI over IVF is that lower quality sperm can be used since the sperm does not have to penetrate the zona pellucida. The success rate of ICSI is 23-44% blastocyst development.<ref>Galli, Cesare, Roberto Duchi, Silvia Colleoni, Irina Lagutina, Giovanna Lazzari. Ovum pick up, intracytoplasmic sperm injection and somatic cell nuclear transfer in cattle, buffalo and horses: from the research laboratory to clinical practice. Theriogenology 81 (2014); 138-151.</ref><ref>Katrin Hinrichs. Update on equine ICSI and cloning. Theriogenology 64 (2005); 535-541.</ref>

The world's first cloned horse, [[Prometea]], was born in 2003.<ref>{{cite web|url=https://www.newscientist.com/article/dn4026-worlds-first-cloned-horse-is-born.html|title=World's First Cloned Horse is Born|date=August 6, 2003|author=Shaoni Bhattacharya|access-date=2012-05-30}}</ref> Other notable instances of horse cloning are:
* In 2006, [[Scamper (horse)|Scamper]], an extremely successful [[barrel racing]] horse, a [[gelding]], was cloned. The resulting [[stallion]], Clayton, became the first cloned horse to stand at [[stud (animal)|stud]] in the U.S.<ref name="Brown">{{cite web|url=http://www.thehorse.com/ViewArticle.aspx?ID=13107 |title=Brown, Liz. "Scamper Clone Offered for Commercial Breeding" ''The Horse'', online edition, November 15, 2008 |publisher=Thehorse.com |date=2008-11-15 |access-date=2012-12-11}}</ref>
* In 2007, a renowned show jumper and [[Thoroughbred]], [[Gem Twist]], was cloned by [[Frank Chapot]] and his family.<ref>{{cite web|url=http://www.horsetalk.co.nz/news/2008/09/105.shtml#axzz4G2nfuyfG |title=Clone of top jumper Gem Twist born|publisher=horsetalk.co.nz|date= September 17, 2008 |archive-url=https://web.archive.org/web/20120707044237/http://www.horsetalk.co.nz/news/2008/09/105.shtml#axzz4G2nfuyfG |archive-date=July 7, 2012}}</ref> In September 2008, Gemini was born.<ref>{{cite web |title=Gemini CL xx |url=https://www.superiorequinesires.com/stallion.php?Gemini-CL-xx-1020 |website=Superior Equine Sires, Inc.}}</ref> Other clones followed, leading to the development of a breeding line from Gem Twist.<ref>{{cite web |title=Murka's Gem |url=https://www.chronofhorse.com/classifieds/murkas-gem/ |website=The Chronicle of the Horse}}</ref> 
* In 2010, the first lived equine cloned of a [[Criollo horse]] was born in Argentina, and was the first horse clone produced in Latin America.<ref>{{cite journal|title=Equine Cloning: In Vitro and In Vivo Development of Aggregated Embryos|doi=10.1095/biolreprod.112.098855|pmid=22553223|year=2012|journal=Biol Reprod|volume=87|issue=1|pages=15, 1–9 |author=Andrés Gambini |author2=Javier Jarazo |author3=Ramiro Olivera |author4=Daniel F. Salamone |doi-access=free|hdl=11336/16296|hdl-access=free}}</ref> In the same year a cloned polo horse was sold for $800,000 - the highest known price ever paid for a polo horse.<ref name=PoloHorses>{{cite web|last1=Cohen|first1=Haley|title=How Champion-Pony Clones Have Transformed the Game of Polo|url=http://www.vanityfair.com/news/2015/07/polo-horse-cloning-adolfo-cambiaso|website=VFNews|publisher=Vanity Fair|access-date=27 December 2015|date=31 July 2015}}</ref> 
* In 2013, the world-famous<ref name=Cambiaso>{{cite news|last1=Alexander|first1=Harriet|title=Argentina's polo star Adolfo Cambiaso - the greatest sportsman you've never heard of?|url=https://www.telegraph.co.uk/sport/othersports/polo/11279663/Argentinas-polo-star-Adolfo-Cambiaso-the-greatest-sportsman-youve-never-heard-of.html |archive-url=https://ghostarchive.org/archive/20220112/https://www.telegraph.co.uk/sport/othersports/polo/11279663/Argentinas-polo-star-Adolfo-Cambiaso-the-greatest-sportsman-youve-never-heard-of.html |archive-date=2022-01-12 |url-access=subscription |url-status=live|access-date=27 December 2015|publisher=The Telegraph|date=8 December 2014}}{{cbignore}}</ref> polo star [[Adolfo Cambiaso]] helped his high-handicap team La Dolfina win the Argentine National Open, scoring nine goals in the 16-11 match. Two of those he scored atop a horse named Show Me, a clone, and the first to ride onto the Argentine pitch.<ref>{{cite web|url=http://www.outsideonline.com/news-from-the-field/Game-of-Clones.html|title=Game of Clones|author=Ryan Bell|work=Outside Online|date=10 December 2013}}</ref><ref>[https://www.science.org/content/article/six-cloned-horses-help-rider-win-prestigious-polo-match Six cloned horses help rider win prestigious polo match] - Jon Cohen, Science Magazine, 13 December 2016</ref>