Production of sheep-goat chimeras by inner cell mass transplantation.

Embryos were surgically flushed from goats and sheep on d 6 and 7, respectively, following the first day of estrus (d 0). After enzymatic removal of the zonae pellucidae, inner cell masses were isolated from caprine blastocysts by immunosurgery. The intact inner cell masses were injected into ovine blastocysts with the aid of a micromanipulator. Twenty-two manipulated blastocysts were surgically transferred into 12 ovine recipients. Nine ewes gave birth to a total of 13 young (59% embryo survival). Ten were classified by serum electrophoretic assays or karyotypes as lambs, one as a kid, and two as interspecific chimeras.