Effect of Number of Embryos and Uterine Space on Embryo Survival in the Pig

The uterine space available per embryo was changed from normal by varying the number of embryos or the length of the uterus in 130 pregnant gilts. Embryo survival rate was unaffected when the uterine space per embryo was greater or smaller than normal. Only when the average number of embryos was at least 14 did it appear likely that intrauterine crowding was a possible limiting factor in embryonal survival. Intrauterine crowding is therefore unlikely to be an important factor in early embryonal losses under usual conditions.