Zoo performs first reverse vasectomy on horse
WASHINGTON (AP) - June 17, 2008 Veterinarians said Monday that the surgery was performed in
October 2007 on a Przewalski horse named Minnesota.
Luis Padilla, the zoo veterinarian who performed the reversal
surgery, said the procedure was a first for this species and likely
for any endangered species.
The horses are native to China and Mongolia and were declared
extinct in the wild in 1970. Since then several hundred have been
bred and reintroduced to the wild in Asia.
"This is kind of interesting turnaround," said Dr. Sherman
Silber, a St. Louis urologist who pioneered reversible vasectomies
in 13,000 humans and helped with the horse surgery. "We've made so
much progress because the human really is the perfect model."
A similar surgery was successfully performed while Padilla was a
resident at the Saint Louis Zoo in 2003 on South American bush
dogs, which resemble Chihuahuas. They are classified as vulnerable
but not endangered.
The "temporary vasectomy" could have a significant effect on
how animals are managed in captivity by giving zookeepers a new way
to control the animal's offspring without having to neuter them or
use contraceptives that can change an animal's behavior.
Minnesota, the 20-year-old horse, had a vasectomy in 1999 at his
previous home at the Minnesota Zoo. A vasectomy may be performed on
an endangered animal because of space constraints, the size of
species or if an animal has already produced many offspring and its
genes are overrepresented in the population, said Budhan
Pukazhenthi, a reproductive scientist at the National Zoo's
Conservation and Research Center in Front Royal, Va.
Scientists later realized Minnesota was one of the most
genetically valuable horses in the North American breeding program
based on his ancestry. Zookeepers hope to find a suitable female
for Minnesota in July.
Cheryl Asa, director of the American Zoo and Aquarium
Association's Wildlife Contraception Center, said the reversible
vasectomy could be useful in isolated cases but probably won't be
adopted broadly.
---
On the Net:
National Zoo: http://nationalzoo.si.edu
