Reverse Vasectomy (IMAGE) Smithsonian Caption Veterinarians at the Smithsonian's National Zoo have performed a successful reverse vasectomy on a Przewalski's horse named Minnesota. This is the first procedure of its kind to be performed on an endangered equid species. Credit Smithsonian’s National Zoo Usage Restrictions None License Licensed content Disclaimer: AAAS and EurekAlert! are not responsible for the accuracy of news releases posted to EurekAlert! by contributing institutions or for the use of any information through the EurekAlert system.