Friday, October 08, 2021

Assisted reproductive techniques: online collection

Assisted reproductive techniques are becoming more common in equine breeding, not least within the sport horse world. The Equine Veterinary Journal (EVJ) is sharing the latest knowledge on assisted reproductive techniques (ARTs) through a special virtual collection that is free to view until 27 December 2021.


While the main reason for developing the ARTs was their potential to accelerate genetic improvement by allowing more offspring to be produced from the best stallions and/or mares, early uptake in practice has been biased towards their capacity to salvage the breeding career of valuable horses suffering from persistent sub-fertility. Editor Tom Stout and guest editor Huw Griffiths have brought together a collection of 14 selected articles published recently in EVJ that have contributed to the advance of equine ARTs. 

Photo of an oocyte immediately after sperm injection. The sperm can be seen in the middle of the oocyte. The small round ball at the top of the oocyte is the first polar body - showing that the oocyte is mature and ready for fertilization

“While some ERT techniques such as embryo transfer and in vitro production are technically complex and not yet optimised, they have proven to be powerful techniques for resolving sub- fertility,” said Tom Stout. “Further studies into factors limiting their success may not only lead to future improvements but also yield information useful to tackling specific causes of sub-fertility in mares or stallions used for natural mating or AI. This collection shares current knowledge.”


Ensuring that mating or artificial insemination (AI) take place close to the time of ovulation is a central part of successful breeding management. Several articles cover aspects of ensuring sperm and egg meet at the optimal time and in optimal conditions. Another discusses the challenges of creating an appropriate environment for early embryo development. 


In vitro production (IVP) has only become commercially viable in equine practice during the past 10 years. Parts of the collection cover the development of IVP and some of the obstacles encountered including incidences of monozygotic multiple pregnancies and potential problems with the mare of advanced age. 


An advantage of IVP is that the embryos are amenable to cryopreservation with no appreciable difference in pregnancy rates between freshly transferred and cryopreserved ICSI embryos. Several articles discuss methods of cryopreservation and vitrification protocols.

“As our knowledge progresses so does our capacity to use ARTs to best effect, to preserve important lineages, reduce inherited disease risks and enhance welfare,” said Professor Celia Marr, Editor of the EVJ.

“This collection makes for invaluable reading, not only for those working in equine reproduction but for those vets who have a general interest in the continued advancement of science and the inextricable and growing links ART has to successful equine breeding.”

The virtual issue will be free to view until 27 December 2021, and can be found at:

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