The cleavage rate and blast rate for lymphocyte and skin fibroblast-derived cells were not significantly different among the three individual donors (animals) in the present study. In our previous study too, we found similar blastocyst rate for milk- and skin fibroblast-derived among individual animals l 191. This suggests that the between-animal variation may not be a major factor influencing the blastocyst rate. However, Shi et al. [221 re- ported the variable blastocyst rate from buffalo fetal fi- broblasts obtained from different donor animals