The National Zoo's female giant panda was artificially inseminated yesterday, and staff members at the animal park said they are "feeling good" about the chances of a cub being born in the next three to six months.
"It was quick, safe," said Jo Gayle Howard, a reproductive scientist at the zoo who performed the procedure at the Panda House. "We think we have a good chance of success."
Veterinarians Suzan Murray, left, Sharon Deem and Ellen Bronson prepare female giant panda Mei Xiang for artificial insemination.
(Photos Jessie Cohen -- Smithsonian Institution)
The Panda House, closed to the public since last week, remained off limits yesterday. Zoo spokeswoman Peper Long said the outdoor panda yard probably will be reopened today.
The zoo turned to artificial means after several failed mating attempts Thursday and early yesterday. The pandas -- Mei Xiang and male Tian Tian -- exhibited plenty of breeding behavior but never quite consummated their brief annual fling.
After another failed attempt early yesterday, and with hormone tests showing that Mei Xiang was at peak estrus, or heat, the zoo decided that it could no longer let nature take its course. In a telephone interview yesterday afternoon, Howard, head veterinarian Suzan Murray and veterinarian Sharon Deem discussed the artificial insemination procedure and the latest panda mating efforts.
Tian Tian, they said, was anesthetized in his training cage at 6:30 a.m. for sperm collection. As he was waking up, Mei Xiang was anesthetized and the sperm was placed in her uterus. She recovered about 45 minutes later. The entire procedure took about 4 1/2 hours.
The zoo artificially inseminated Mei Xiang last year after the pandas failed to mate. But she was not anesthetized for that procedure, and the sperm could not be placed very far up in her reproductive tract. No pregnancy occurred. This time, with the panda anesthetized, Howard said she was able to deposit the sperm directly into the uterus.
Artificial insemination has been used with giant pandas in China, with a 60 percent success rate, and at the San Diego Zoo, where one of its two cubs was conceived with this method. For yesterday's procedure, Howard said she used a laparascope with a thin plastic catheter, or hollow tube, that was three times as long as what is used in China, enabling her to reach farther into the uterus.
"We are all feeling good" about how well the procedure went, she said.
Zoo scientists said there is no definitive test that would confirm a pregnancy. It could take three to six months for a cub to be born, depending on when the egg is implanted. If nothing happens in six months, they said, it will mean Mei Xiang did not get pregnant.
Mei Xiang, 6, and Tian Tian, 7, arrived from China in 2000. They mated for the first -- and only -- time in April 2003, but no pregnancy resulted. The pandas are in the fifth year of a 10-year loan from China, at a cost of $10 million a year.
About 1,600 pandas are left in the mountain forests of central China and about 140 in breeding facilities and zoos.
Mating season came earlier than usual to the Panda House this year, although the normal breeding period for giant pandas is between February and May. There are usually only two to three days a year for optimal mating.
With the Panda House closed, those who follow the annual mating ritual had to rely on the webcam at the zoo's Web site. On Thursday, when Mei Xiang and Tian Tian were showing the most interest in each other, the giant panda link logged nearly 13,000 hits by the curious public, compared with about 5,000 visits the day before.
The zoo's previous panda pair, Ling-Ling and Hsing-Hsing, produced five cubs, the last born in 1989. But none lived longer than a few days. Efforts to breed them were hampered by several factors.
It took years before the pair got along well enough to even try to mate. By the time mating occurred and cubs were born, the female panda was no longer young. Her cubs either got sick shortly after birth or were born ailing.
"In the past, we had a geriatric female who had a history of urinary tract infections that may or may not have been related to the cub deaths," Murray said. "Now, we have a much younger, healthy female. There is probably a better chance for a successful cub birth if the babies are born to younger females."
Although the current panda pair has had problems coordinating mating efforts, the zoo said Tian Tian seemed to be catching on Thursday night and did his best job yet of trying to align himself with Mei Xiang. By yesterday, however, he had lost interest.
"It's a learning process for him," Howard said.