Scientists reverse vasectomy on endangered horse

Scientists at the National Zoo say they have reversed a vasectomy on an endangered horse — the first known operation of its kind on an endangered species.

Veterinarians revealed Monday that they successfully performed the procedure on the horse to allow it to reproduce naturally. The surgery was performed in October 2007 on a Przewalski horse named Minnesota. The horses are native to China and Mongolia.

Luis Padilla, the zoo veterinarian who performed the surgery, says the procedure was a first for this species and likely for any endangered species. The team worked with St. Louis urologist Dr. Sherman Silber, who pioneered the technique in humans.

A similar surgery was successfully performed at the Saint Louis Zoo in 2003 on South American bush dogs, which are classified as vulnerable but not endangered.

The ''temporary vasectomy'' could have a significant impact on how animals are managed in captivity by giving zookeepers a way to control the animal's offspring without having to neuter them.