Giant Panda Pregnancy Update

Photo by PoPville flickr user ep_jhu

From the National Zoo:

Spring has sprung and the giant pandas are breeding again at the Smithsonian’s National Zoo. Scientists detected a rise in urinary estrogens March 26, in its female giant panda Mei Xiang (may-SHONG). This rise and her behaviors indicated that Mei Xiang was in estrus and ready to breed. A team of Zoo scientists and veterinarians, including Tang Chunxiang, the assistant director and chief veterinarian of the China Conservation and Research Center for the Giant Panda at Wolong, performed an artificial insemination (AI) earlier this morning [Saturday] after keepers determined no competent breeding between Mei Xiang and the Zoo’s male giant panda Tian Tian (tee-YEN tee-YEN) had occurred overnight.

“We are hopeful that our breeding efforts will be successful this year, and we’re encouraged by all the behaviors and hormonal data we’ve seen so far,” said Dave Wildt, head of the Center for Species Survival at the Smithsonian Conservation Biology Institute. “We have an extremely small window of opportunity to perform the procedures, which is why we monitor behavior and hormones so closely.”

Mei Xiang was put under general anesthesia for the artificial insemination and will likely undergo a second procedure later today. During the artificial insemination, the team of scientists and veterinarians used a combination of fresh semen collected from Tian Tian early this morning and frozen semen collected from Tian Tian in 2003.

The Zoo’s plans for breeding Mei Xiang and Tian Tian were developed in accordance with the Giant Panda Cooperative Research and Breeding Agreement, which lasts until 2015. Tang traveled to the Zoo to assist with breeding as part of the agreement. He performed two artificial inseminations on Mei Xiang alongside a team from the Zoo in 2011.

Zoo scientists will monitor Mei Xiang’s hormone levels in the coming months and conduct ultrasounds to determine if she is pregnant. A pregnancy lasts between 95 and 160 days. Female giant pandas experience delayed implantation, during which the embryo does not implant in the uterine wall until a few weeks before birth and a fetus does not start to develop until the final weeks of gestation. It is impossible to determine from behaviors and hormone analyses alone if a female is pregnant or experiencing a false pregnancy (pseudopregnancy).

More details after the jump.

Reproductive scientists and veterinarians from the Smithsonian’s National Zoo alongside Tang Chunxiang, the assistant director and chief veterinarian of the China Conservation and Research Center for the Giant Panda at Wolong performed a second artificial insemination on giant panda Mei Xiang Saturday, March 30, around 6 p.m.

During the first artificial insemination scientists used a combination of fresh and frozen semen from Tian Tian. For the second procedure, Mei Xiang was artificially inseminated with frozen semen from two different males.

Scientists used thawed semen collected from the San Diego Zoo’s male giant panda, Gao Gao, in 2003. They then used thawed semen collected from Tian Tian in 2003. Mei Xiang was inseminated with semen from Gao Gao in 2007, but she did not give birth to a cub.

A wild-born male giant panda, Gao Gao arrived at the San Diego Zoo on Jan. 15, 2003, from the People’s Republic of China as part of the Zoo’s research loan. He was born in China’s Baoxing County but was kept in the Fengtongzhai Rescue Center for most of his early life after reintroduction efforts failed to keep him out of areas inhabited by humans. He was transferred to the Wolong Nature Reserve prior to his journey to the San Diego Zoo. Gao Gao had shown interest in female pandas in Wolong; however, he had not fathered any offspring until his arrival in San Diego. He is the sire of five cubs born to Bai Yun at the San Diego Zoo: Mei Sheng, Su Lin, Zhen Zhen, Yun Zi and Xiao Liwu.

Both Mei Xiang and Tian Tian have recovered from the procedures over the weekend and are doing well. The Zoo will run a paternity analysis if a cub is born. The David M. Rubenstein Family Giant Panda Habitat reopened to the public yesterday, March 31, and visitors can see both Mei Xiang and Tian Tian.