Scientists Work to Save Persian Onager from Extinction

Scientists Work to Save Persian Onager from Extinction

This is one of the two live Persian onager foals born via artificial insemination.

Photo: Mandi Schook, PhD

What do you do when you’ve got an endangered species of wild equid and your genetically matched mare and stallion are hundreds or even thousands of miles apart? Just round up said wild stallion and take him to your local breeding station so he can mount the dummy, right? Not exactly. And boarding him on a plane for a round-the-world tour isn’t exactly in his best welfare interest either—nor is it likely to be financially feasible, especially when budgets are limiting.

But breeding Persian onager stallions to mares in different parts of the world is exactly what scientists hope to accomplish in an effort to save the endangered species. Persian onagers are a rare species of Asian wild ass, native to Iran, which are today considered to be “critically endangered,” said Budhan S. Pukazhenthi, BVSc, PhD, reproductive physiologist at the Center for Species Survival in the Smithsonian Conservation Biology Institute (SCBI), in Front Royal, Virginia.

Although onagers breed naturally in zoos, Pukazhenthi said the goal is to reduce the risks of inbreeding. Currently there are fewer than 1,000 animals worldwide (including fewer than 30 in North American zoos).

The solution? Artificial insemination.

Mandi Schook, PhD, associate research curator at the Cleveland Metroparks Zoo, in Cleveland, Ohio, accepted the challenge of collecting semen from male onagers and inseminating females.

In a pioneering effort, Schook and colleagues succeeded in harvesting viable sperm through electroejaculation (electrical stimulation of pelvic muscles causing ejaculation) of seven anesthetized male onagers in American zoos. The sperm survived freezing and thawing and were implanted into three sedated female onagers at the Wilds, a SCBI partner institution in Cumberland, Ohio.

But before the insemination could occur, scientists had to first establish the females' basic reproductive biology—a critical step, Schook said, as not all equid species have the same kinds of reproductive cycles. Researchers examined a group of females twice by ultrasound, without sedation, prior to insemination. They also monitored the hormone metabolites in their urine. With the information they gathered, the researchers determined the appropriate timing for a successful insemination.

But before the insemination could occur, scientists had to first establish the females' basic reproductive biology—a critical step

Photo: Courtesy Dr. Mandi Schook

All in all, the females received very little handling—a maximum of two times prior to insemination—and sedation only during the actual insemination process, when the mares received a 10- to 15-minute standing sedation.

“In the time it takes for a sedative to be administered and take effect, we can be done with the ultrasound exam and the female returned directly to her enclosure with the other females, where a grain reward is waiting,” Schook said.

Out of three inseminated onagers, two live foals were born—one from fresh, chilled semen and the other from frozen, then thawed semen, Schook said.

“Transporting a single endangered equid overseas for population management can cost upwards of $20,000,” Schook said. “Therefore, artificial insemination provides a means to manage these populations more globally by the transport of genetic material at a lower cost and with less risk to the animal.

“This also means that we could potentially bank genetic material (frozen sperm) from animals in the wild, without having to remove them from their environment, an additional ‘insurance policy’ against any unseen catastrophe (that could lead to extinction),” she added.

With the successful artificial insemination protocol, Schook said researchers now have hope of strengthening Persian onager numbers in the coming years.

The study, "Fundamental studies of the reproductive biology of the endangered persian onager (Equus hemionus onager) result in first wild equid offspring from artificial insemination," was published in Biology of Reproduction

About the Author

Christa Lesté-Lasserre, MA

Christa Lesté-Lasserre is a freelance writer based in France. A native of Dallas, Texas, Lesté-Lasserre grew up riding Quarter Horses, Appaloosas, and Shetland Ponies. She holds a master’s degree in English, specializing in creative writing, from the University of Mississippi in Oxford and earned a bachelor's in journalism and creative writing with a minor in sciences from Baylor University in Waco, Texas. She currently keeps her two Trakehners at home near Paris. Follow Lesté-Lasserre on Twitter @christalestelas.

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