Effects of age and body mass of recipients on survival of transferred embryos in mice.

To examine the effects of age and body mass of recipients on embryo survival during gestation, ICR embryos were transferred to nulli- or primi-parous females of 4 strains of mice. Out of 530 recipients, 383 (72.3%) produced a litter. Transfer of 3,465 embryos to 383 recipients resulted in production of 1,637 pups born alive, an overall rate of embryo survival of 47.2 +/- 1.1%. Regression analyses revealed that embryo survival decreased in older recipients and increased in heavier recipients. The results were consistent in each parity/strain group and all groups combined.