Karyotypes of 3- or 4-day-old pig embryos after short in-vitro culture

Pig embryos (3-4 days old) were grown for approximately 21 h in microdroplets under mineral oil with vinblastin sulphate as the mitotic inhibitor. From 10 gilts, 115 eggs were cultured: 8 proved to be unfertilized oocytes, 9 did not contain mitotic figures, 16 contained fewer than 3 good mitotic figures and 80 were judged to be of normal karyotype. A few polyploid cells were encountered, possibly of trophoblast origin. One embryo was a haploid and another one a 2N/6N mixoploid. In one gilt, in which there was no evidence of fertilization, a tetraploid embryo was discovered, and was assumed to be parthenogenetic.