I recently returned to the US for a break from work in Africa and am enjoying access to fast Internet--it makes keeping up with the latest news much easier! One story caught my eye immediately: "First Reverse Vasectomy Success in an Endangered Species at the National Zoo."

A team of vets--many of whom I've worked with in the past--succeeded in reversing a vasectomy in a Przewalksi's Horse. They worked with physician Dr. Sherman Silber, a pioneer in the development of reverse vasectomies in humans, a technique that requires microsurgery. Dr. Silber had previously worked with vets at the St. Louis Zoo to develop a technique for this procedure in South American bush dogs, also an endangered species.

The first surgery on the P-horse (I'll call him that for short) required six hours and didn't work, apparently owing to scar tissue from the original surgery performed in 1999 at another institution. The team discussed their options. Dr. Silber felt the animal's positioning was the key. After more planning and discussion, the team repeated the surgery with the P-horse on his back. It took just one hour, and this time it worked.

This case is a great example of medical cross-over. Extrapolation is the rule rather than the exception in zoological medicine. We often apply medical techniques developed for humans and domestic animals to endangered animals. Success depends on teamwork, persistence, and, to a certain extent, trial and error.

I also appreciated Dr. Silber's comment that he'd always dreamed of helping wildlife. He may never have imagined using his skills to operate on a bush dog or a P-horse. But now he's become a world-reknowned expert, and I've no doubt he'll be asked to help additional species and to train other doctors in the procedure.

There's another reason this story grabbed my attention. I remember visiting the National Zoo's Conservation and Research Center (CRC) several years ago in my capacity as director and talking with the staff there about the future of the Przewalksi's Horse. They're striking animals to see in the middle of a pasture, and CRC had several dozen of them, including a small herd of older females and several bachelor males. Years earlier, the CRC had offered to house P-horses who had been taken out of the breeding pool, and now the animals were living out their lives quietly.

At the time of my visit, several institutions had recently resumed breeding P-horses as part of a program to reintroduce this species back to Mongolia. Given the National Zoo's expertise in reproductive physiology, conservation genetics, endangered species reintroduction, and clinical medicine, we discussed the possibility that CRC might one day take an active part in P-horse breeding.

Everyone agreed that the first step would be to evaluate the reproductive health and genetics of the individual animals and go from there. Clearly, a lot has happened since then! For the full story, go to Science Daily: "First Successful Reverse Vasectomy On an Endangered Species at the National Zoo."

There's a lot more to the P-horse reintroduction story. A good place to start is the WAZA website, which has many links to details about wild equid conservation.

Dr. Christian Walzer, who has led the reintroduction effort of several wild equids in in Mongolia, is a contributor to Ted's and my new book. His story, A Camel in the Snow, takes place in the Gobi Desert.