The efficacy of the well of the well (WOW) culture system on development of bovine embryos in a small group and the effect of number of adjacent embryos on their development.

The aim of the present study was to clarify the efficacy of the well of the well (WOW) culture system for a small number of embryos and the effect of number of adjacent embryos in a WOW dish on blastocyst development. In conventional droplet culture, embryos in the small-number group (5-6 embryos/droplet) showed low blastocyst development compared with a control group (25-26 embryos/droplet). However, small and large numbers of embryos (5-6 and 25 embryos, respectively) in a WOW dish showed no significant differences in cleavage, blastocyst rates, and mean cell number in blastocysts compared with the control group (25-30 embryos/droplet). In addition, the number of adjacent embryos in a WOW dish did not affect the development to blastocysts and cell number in blastocysts. In conclusion, a WOW dish can provide high and stable blastocyst development in small group culture wherever embryos are placed in microwells of the WOW dish.