10 November 1995

Quicker transfer with thawed embroys

EMBRYO transfer will be easier now that a technique enabling direct transfer of frozen embryos on thawing to recipient females has reached commercial fruition.

The ET industry will benefit, said Dr Neimann, Mariensee, Germany, speaking at the 30th symposium on reproduction and animal breeding in Milan, because less time will be needed to process frozen embryos for transfer. There will also be no need for lab equipment at the point of transfer; it would be easier to use recipients; and the transfer could be carried out by a lay technician or producer rather than a specialist.

Currently embryos are frozen and thawed in a controlled process which uses slow cooling to temperatures of -30- -40C (-22- -40F).

Dr Neimann suggests the new technique will offer several advantages over slow freezing.

It avoids the need for an expensive freezing machine; no ice is formed to damage the embryo; and the ethylene glycol (EG)-based vitrification solution is less toxic to the embryo. The technique could also enable breeders to set up a "genetic bank" of known-sex (embryos fertilised in the lab using sexed semen) embryos ready for direct transfer to recipients on thawing. &#42