Page 453 - Equine Clinical Medicine, Surgery and Reproduction, 2nd Edition

428 CHAPTER 2

VetBooks.ir 2.25 2.26 2.27

Figs. 2.25–2.27 (2.25) The straws containing the frozen semen should be stored in liquid nitrogen and
carefully labelled to avoid incorrect insemination. (2.26) The straws are thawed in a temperature-controlled
water bath before insemination. (2.27) Insemination of a mare with frozen semen using an insemination pipette.

• Insemination of thawed frozen semen has facility where suitable recipient mares are kept. The
been associated with a severe inflammatory procedure allows mares to remain in competition
reaction in some mares and this will require while producing foals and allows mares with physi-
post-insemination assessment at 6–8 hours with cal injuries that prevent them carrying a foal to still
uterine lavage, intra-uterine antibiotics and breed. In high-class mares it is possible through ET
systemic oxytocin treatment as necessary. to increase the number of foals they can produce
in their lifetime. Recent advances in superovula-
Preparation of the mare for any AI tion techniques and more widespread acceptance by
• Empty the rectum. breed societies are now resulting in increased use of
• Wrap the tail in a plastic sleeve and hold it to this technique in mares, but the procedure can be
one side. time-consuming and expensive and is therefore used
• Wash perineal region thoroughly with clean, most often in valuable mares.
warm water and dry. Cryopreservation of embryos means that preg-
• Use a clean plastic rectal sleeve. nancy can be delayed if required, although suc-
• Use a non-spermicidal lubricant. cess rates may be lower using frozen embryos. The
• When using fresh or chilled semen the material technique of oocyte transfer has been developed
is drawn into a non-toxic syringe (latex free) and in recent years in order to help obtain pregnancies
a sterile insemination pipette. from problem, older mares where ET has very poor
success rates. This involves the transfer of a donor’s
EMBRYO TRANSFER oocyte into the oviduct of a recipient. In-vitro fer-
tilisation and cloning techniques are currently being
Overview researched.
Embryo transfer (ET) donor mares are mated and
the resulting fertilised ova harvested and either Technique
stored using cryopreservation, implanted into a Synchronisation of oestrus between the donor
recipient mare directly or sent to a central ET and recipient mares is essential to success, ideally