Random header image... Refresh for more!

Pushing the Envelope on Frozen Semen Fertility with Gek the Pallas’ Cat

Back in the early 1990s, an eager young post-doctoral fellow was hired to study cat reproduction at the Smithsonian’s National Zoological Park. One of his first projects involved a small-sized, little-known Central Asian felid called the Pallas’ cat (Otocolobus manul).

Pallas' cat (Photo: Cassandre Crawford)

Pallas’ cat on exhibit in Night Hunters (Photo: Cassandre Crawford)

At the time, there was a grand total of one male Pallas’ cat in all U.S. zoos – a wild-born Mongolian cat named Gek. The post-doc dutifully collected and evaluated Gek’s semen every two months for almost two years and, for the first time, documented the extreme reproductive seasonality typical of this species. Concurrently, he froze Gek’s semen for long-term storage.

Fast forward 22 years later. That post-doc, Dr. Bill Swanson, is now CREW’s Director of Animal Research, and in early 2015, found himself in desperate need of frozen Pallas’ cat semen. Fortuitously, he previously had acquired Gek’s samples from the National Zoo. Frozen semen from Gek and two other males was used for laparoscopic oviductal artificial insemination (LO-AI) of four Pallas’ cats at three U.S. zoos (Cincinnati, Columbus, Pueblo). Two of those cats appeared to conceive; however, only the Columbus Zoo female subsequently gave birth. Her single kitten was fully developed, but, unfortunately, stillborn.

Dr. Swanson with his little buddy Gek in 1993

Dr. Swanson with his little buddy Gek in 1993

Notably, the father of that kitten was … (drum roll, please) …Gek! The pregnancies and birth were the first ever with frozen semen in Pallas’ cats but also established a new longevity record for frozen semen fertility in any wildlife species. Additional LO-AIs using Gek’s frozen samples are planned for 2016 – hopefully followed by the birth of healthy kittens this time around. Long-live Gek!

(Funded by the Institute of Museum and Library Services)

February 12, 2016   3 Comments

A RARE Endeavour: CREW Scientists Assist Rhino Reproduction

With a history of verified results from collaborative research, CREW scientists understand the importance of developing
scientific capacity within individuals and organizations throughout North America to overcome the serious loss of
genetic diversity facing captive African and Asian rhino populations.

Indian rhino (Photo: DJJAM)

Indian rhino (Photo: DJJAM)

In the first year of a three-year National Leadership Grant from the Institute of Museum and Library Services (IMLS), CREW
has begun building a Rhino Assisted Reproduction Enterprise (RARE) in collaboration with SeaWorld Busch Gardens Reproductive Research Center and several other zoos accredited by the Association of Zoos & Aquariums. These zoos contribute the veterinary and rhino keeper staff time needed to learn and implement rhino assisted reproductive techniques,
with the necessary training, tools and laboratory support provided by CREW.

One objective of the grant is to contribute to the genetic management and propagation of captive Indian rhinos through artificial insemination (AI). Although AI in Indian rhinos is still a work in progress, the achievements made during CREW’s initial 8-year effort are impressive with six conceptions and four term calves produced. Because there is a steep learning curve to these procedures, we are hopeful that success will become even more common over time. Participating zoos agree to collect and ship rhino urine samples on a frequent basis to CREW for hormone analysis needed to time AI. Rhino keeper staff at each facility condition females to enter a chute for the purpose of performing AI and the standing sedation protocol already established for successful intrauterine AI in this species is implemented prior to expected ovulation date. Each facility observes one AI before performing the next AI under CREW supervision.

Dr. Monica Stoops (CREW) and Dr. Anneke Moresco (Denver Zoo) discuss results of an ultrasound exam conducted on a sedated female Indian rhino.

Dr. Monica Stoops (CREW) and Dr. Anneke Moresco (Denver Zoo) discuss results of an ultrasound exam conducted on a sedated female Indian rhino.

We are happy to report that the Denver Zoo team is now fully trained in Indian rhino AI and is performing procedures in house using sperm from CREW’s CryoBioBank. Our long-term commitment to rhino conservation has positioned us to respond to the growing need of zoos to build their capacity for assisted reproductive technology for rhinos. We are gladly meeting this challenge and enjoying establishing a network of RARE researchers united for a common cause – to save rhinos. A RARE endeavor indeed.

February 8, 2016   2 Comments

Glass Glass Baby: Birth of Healthy Kittens following Sperm Vitrification for Artificial Insemination

A world leader in small cat reproductive research, our Center for Conservation and Research of Endangered Wildlife (CREW) has successfully produced the first non-human offspring – two kittens – using vitrified sperm (semen preserved as glass instead of ice) for artificial insemination (AI).  Dr. Bill Swanson explains the significance of this breakthrough in this video.

Vito and Elsa, kittens produced from vitrified sperm

Vito and Elsa, kittens produced from vitrified sperm

Cryopreservation of cat semen for assisted reproduction can be challenging, requiring technical expertise and specialized equipment for semen collection, processing and freezing. As a simplified alternative to standard semen cryopreservation methods, CREW scientists have been investigating the use of vitrification – the ultra-rapid cooling of liquids to form a solid without ice crystal formation. This approach essentially preserves semen as glass instead of ice.

For vitrification, cat semen is diluted in a chemically-defined medium containing soy lecithin and sucrose as cryoprotectants and, after a five minute equilibration period, pipetted in small volumes (~30 microliters) directly into liquid nitrogen to form tiny glass marbles of frozen sperm.

In initial studies, we found that cat sperm survived vitrification as successfully as that frozen using standard straw freezing methods and that vitrified sperm were capable of fertilizing cat oocytes in vitro. In our first assessment of in vivo viability, eight of these embryos were transferred into three synchronized females. Although one female appeared to have two early implantations, no offspring were produced.

In a follow-up study, artificial insemination (AI) with vitrified sperm was assessed in three additional females. With our laparoscopic oviductal AI technique (LO-AI), only a couple million sperm are required per insemination, allowing the use of the relatively low sperm numbers that are preserved in vitrified semen pellets. Following LO-AI with vitrified sperm, all three females conceived, with two of the pregnancies progressing to term and culminating in the birth of two healthy kittens in early April. These kittens, a male named Vito (short for vitrification) and a female named Elsa (after the character in the movie Frozen), are the first non-human offspring – of any species – produced with vitrified sperm (although three human babies have been born from earlier research).

Vito and his mother, Ebony

Vito and his mother, Ebony

Elsa and her mother, Ivy

Elsa and her mother, Ivy

Our preliminary results with semen from fishing cats and ocelots indicate that vitrification is effective for preserving post-thaw sperm viability and function across cat species. These findings suggest that this fast and simple cryopreservation method may have broad applicability for semen banking of endangered felids housed in zoos and possibly living in the wild.

Jaci Johnson with Elsa and Vito

Jaci Johnson with Elsa and Vito

The study’s lead author, veterinary student Jaci Johnson, has been selected to present these findings at the upcoming American Association of Zoo Veterinarian’s Annual Meeting in Portland, Oregon. (Funded, in part, by the Procter & Gamble Wildlife Conservation Scholarship program in collaboration with Ohio State University’s College of Veterinary Medicine.)

– Reprinted from the Spring 2015 CREW Progress Report

May 14, 2015   1 Comment