Successful Culture in vitro of Bovine Embryos to the Blastocyst Stage

Abstract

Two hundred and sixty bovine embryos between the two- and eight-cell stage were collected from synchronized, PMSG-treated cows. Embryos were placed randomly in culture among 11 media and 2 gas atmospheres and development was recorded at 24 h intervals for the duration of culture. The number of cells present at the cessation of culture was determined following aceto-orcein staining. Ham’s F-1O medium supplemented with heat treated fetal calf serum (HTFC), supported the development of 9 of 43 (21 percent) eight-cell embryos into expanded blastocysts after 134 to 150 h in culture and 1 of the 9 expanded blastocysts appeared to undergo an in vitro hatching process after 160 h in culture. No other media tested supported development of bovine embryos beyond the early blastocyst stage (32 to 64 cells). The reduced oxygen atmosphere of 90 percent N2, 5 percent CO2, 5 percent O2 was superior (P<0.01) to 5 percent CO2 in air in both the number of embryos undergoing division and in degree of development. Ham’s F-10 medium supplemented with HTFC serum under a 90 percent N2, 5 percent CO2, 5 percent O2 gas atmosphere successfully supported the development of four-, six- and eight-cell bovine embryos cultured in vitro.