Piglet production by non-surgical transfer of vitrified embryos, transported to commercial swine farms and warmed on site.

We investigated the feasibility of piglet production by non-surgical embryo transfer (Ns-ET) of vitrified porcine blastocysts and expanded blastocysts transported to commercial farms and warmed on site (V/T/W embryos). Ns-ET was performed by depositing 11-20 vitrified and warmed embryos at a proximal site within the uterus via a catheter. In Experiment 1, the effect of donor-recipient estrous cycle asynchrony on the efficiency of Ns-ET of vitrified and ordinary warmed embryos was investigated at the experimental facility. With a 1-day delay recipients relative to that of donor, the farrowing rate was 50.0% and the survival rate to term was 21.1%. In Experiment 2, Ns-ET using recipients with a 1-day delay and vitrified embryos after one-step warming and dilution was evaluated at the experimental facility. Although the resulting farrowing rate was 42.9%, the survival rate was 6.4%. In Experiment 3, Ns-ET was conducted using V/T/W embryos at four commercial farms, where piglets derived from them were produced. When artificial insemination was conducted prior to Ns-ET, the farrowing and survival rates obtained using V/T/W embryos were 75.0%, and 21.3%, respectively. These results show that Ns-ET of V/T/W embryos using this protocol would be feasible for piglet production at farms.