Is it permissible to sell a cow that has been vowed before she gives birth and donate half her price, even though the vow was to donate half her offspring?

If you made a vow to purchase a cow, this is a binding vow that must be fulfilled in the manner you intended. It is not permissible to sell the vowed cow and donate half of its price, for the fundamental principle is the obligation to fulfill a vow exactly as it was uttered. Some jurists have stipulated the permissibility of dedicating an animal for the purpose of distributing its offspring.