Repeat superovulation, non-surgical embryo recovery, and surgical embryo transfer in transgenic dairy goats

We investigated the capability of repeat superovulation and non-surgical embryo retrieval, coupled with surgical embryo transfer, to expedite the production of transgenic progeny from transgenic founder dairy goat does. In addition, we compared embryo yields, number of embryos transferred per recipient, pregnancy rates, and offspring born during both the traditional (September-December) and non-traditional (January-May) breeding seasons. Although there were no significant differences, there were numerically more transferable embryos recovered per flush (3.5+/-0.9 vs. 2.4+/-0.9 embryos; mean+/-S.E.M.) and increases in both the proportion of recipients that were pregnant (83 vs. 69% pregnant) and offspring born from total embryos transferred (67 vs. 53% offspring) during the traditional versus the non-traditional breeding season. The transfer of one, two or three embryos did not significantly affect the proportion of pregnant recipients during either season. However, there was a difference (P<0.05) in the proportion of offspring produced for one versus two embryo transfers (89 vs. 44% offspring, respectively) during the non-traditional breeding season. Overall, 14 transgenic offspring were produced from 54 total offspring born, and the kidding interval was reduced to <3 months for six of the seven transgenic does. In summary, repeat superovulation and non-surgical embryo retrieval, coupled with surgical embryo transfer, expedited the production of progeny from transgenic founder does.