In a scientific breakthrough, USDA scientists have successfully completed several trials involving pig embryo preservation.

After years of work, researchers at USDA's Agricultural Research Service (ARS) have produced the first live offspring from pig embryos that were "cryopreserved" by stabilized vitrification, according to research physiologist J.R. Dobrinsky.

In the process, embryos placed in a plastic straw are submerged into liquid nitrogen. To prevent cellular disruption during cryopreservation, embryos are stabilized and then cryopreserved to a solidified liquid, in the absence of ice crystals (vitrification). After indefinite storage, straws containing the cryopreserved embryos can be warmed, embryos recovered and then transferred to recipient females.

In the first trial verifying this process, two of the five recipient sows implanted with preserved embryos farrowed 10 normal piglets.

In a second trial, four of seven recipients farrowed 24 live offspring. >From these litters, two boars and two gilts were selected for reproductive tests. Each boar was mated to three gilts. One boar was used naturally, the other was used in artificial insemination. Each gilt was artificially inseminated twice with semen from herd boars. All eight females farrowed normal litters. Select offspring from the second generation litters were raised to maturity, mated and farrowed normal, third generation offspring.

This embryo preservation process will provide a foundation for effective utilization and transport of the world's best genetics globally, modernize pork production and enhance genetic improvement programs.

Researcher: J.R. Dobrinsky, Beltsville Agricultural Research Center, USDA. Phone Dobrinsky at (301) 504-8134 or e-mail