if they are racing the mare is stitched shut until it is done with its racing life because they can run so hard that they tear them selves open. Studs are usually left as studs until they are done racing because you wont no there value until they have won or lost some races. If they are not any good on the track then they are clipped. Mares usually stay stitched shut even after leaving the track unless the owner decides to breed then they un stitch her.