Establishing twin pregnancies in cattle by embryo transfer

Abstract

Various methods of creating twin pregnancies in cattle have been investigated by other authors (see review by Sreenan and Diskin, 1987). However, virtually all of these methods have involved in vivoproduced embryos which, in separate studies, have employed either surgical or non-surgical transfer techniques, where embryos were transplanted either unilaterally or bilaterally in recipients which may or may not have been previously artificially inseminated. There have been no studies where all of these factors were examined collectively, and included with the transplantation of either frozen-thawed in vivoor in vitroproduced embryos. The objectives of the current study were, therefore, to compare pregnancy, twinning and embryo survival rates of recipients in which twin pregnancies were induced by various combinations of embryo source and transfer method to animals inseminated or not prior to embryo transfer, and the distribution of the embryos in the uterus.