Embryo transfer

Embryo transfer

Multiple ovulation and embryo transfer (MOET) is used by deer farmers to maximise the numbers of offspring from genetically elite hinds and stags. It is based on the production of multiple high-merit embryos from each ‘donor’ hind but uses low merit ‘recipient’ hinds as surrogate mothers.

Naturally, hinds produce a single calf annually from a single ovulation event. However, treatment of hinds with various reproductive hormones (principally FSH and eCG) can induce multiple ovulations at time of mating or insemination. Although the hind cannot gestate all the resulting embryos, they can be physically removed from the donor hind and transferred individually into synchronised recipient hinds to be gestated and reared. Thus, it is possible within one season for an elite hind to generate multiple progeny.

What is MOET?
Multiple ovulation and embryo transfer or MOET. MOET involves considerable complex programming and planning, and requires the involvement of highly skilled professionals, including vets and AB technicians. As such, its adoption is largely confined to deer stud operations with high-value recorded female stock. However, commercially available frozen (‘cryopreserved’) embryos are occasionally obtained by commercial breeders (usually by private treaty but sometimes by auction)  to improve the genetic merit of their herds in which case the procedures for embryo transfer into recipient hinds are less complex than for an entire MOET programme.

It is important to remember with a MOET programme, that for each donor hind there are no guarantees of success. The induction of multiple ovulation produces highly variable results between donor hinds within each programme.  Be prepared for some hinds to fail (i.e. no recoverable embryos) while others may be spectacularly successful (i.e. 10-15 recoverable embryos). On average (and ‘averages’ are used a lot in MOET programmes) a programme that yields 4-6 transferrable embryos per donor hind would be considered successful.

The following pages will take you through the various considerations and actions for a successful MOET programme. Remember, as with AI, attention to detail is important.

Show me the science

Fennessy, P.F., Fisher, M.W., Shackell, G.H., Mackintosh, C.G. (1989) Superovulation and embryo recovery in red deer (Cervus elaphus) hinds. Theriogenology 32: 877-883.
Fennessy, P.F., Asher, G.W., Beatson, N.S., Dixon, T.E., Hunter, J.W., Bringans, M.J. (1994) Embryo transfer in deer. Theriogenology 41: 133-138.
Asher, G.W., O’Neill, K.T., Scott, I.C., Mockett, B.G., Pearse, A.J. (2000) Genetic influences on reproduction of female red deer (Cervus elaphus). (2) Seasonal and genetic effects on the superovulatory response to exogenous FSH. Animal Reproduction Science 59: 61-70.

Donor selection (both donor hind and donor stag) is the single biggest consideration of the MOET programme. Let’s face it, MOET is expensive and must target the very best genetics to be financially viable.
The synchronisation and induction of multiple ovulation (sometimes called ‘superovulation’) in donor hinds.
The embryo transfer process and time-frames around scanning post transfer.