Is it permissible to re-divide livestock inherited by sons to the exclusion of daughters, by calculating the value of the sheep at the time of division, and obliging each heir to pay a share to the sisters?

The father's gift of livestock to males to the exclusion of females is an injustice and is invalid. The children must re-divide the livestock justly, with the male receiving the share of two females. This is precisely the correct action and falls under honoring the father after his death.