Technical note: porcine non-surgical embryo transfer.

The cervix is a barrier for transferring porcine embryos non-surgically. A non-surgical embryo transfer instrument composed of four parts has been developed that allows the delivery of embryos into the lumen of one uterine horn. Part 1, a modified artificial insemination spirette, is used to produce a cervical lock and to assist in manipulating Part 2 through the cervix. Part 2 is made of stainless steel tubing with a unique curved tip that can be manipulated through the folds of the cervix. Part 3 is a testing bar to ensure that the tip of Part 2 reaches the bifurcation of the uterus. Part 4, a disposable tubing complex for embryo delivery, is composed of a soft plastic leader tubing, a double opened connector for embryo loading and unloading, a semi-hard plastic tubing, and a hard tubing with a water-sealable plunger. Embryos (4-cell to blastocyst stages) were surgically collected and maintained in vitro up to 5 h before the non-surgical embryo transfer. Five of 16 recipients became pregnant (31%) and farrowed an average of 6.2 +/- 3.1 pigs per litter. This easily learned non-surgical embryo transfer technique will simplify embryo transfer in the swine industry and may lead to improvements in swine breeding and scientific research.