A Blonde Rancher

A blonde has just inherited a Ranch but only had two horses. The problem was she couldn't tell them apart. So she goes to her neighbor rancher and asks for help. He suggests cutting ones tail a bit shorter then the other. She does it but then a week later she comes back and tells the neighbor rancher that it grew back. So he tells her to tie a different colored string around one of the horses neck. She does it but a week later the tie slips off and she has to go back to the neighbor. So he suggest she paint a different color spot on each of the horses. She does and comes back a week later with cookies.
She tells the neighbor rancher, "Here I baked these for you. Your plan worked perfectly. I painted a red spot on the black horse and a blue spot on the white horse."