If attempts at artificial insemination prove successful, a panda pair presented by the mainland to Taiwan is likely to give birth to cubs, according to a leading mainland panda expert.

Tuan Tuan (right) and Yuan Yuan, two pandas presented by the mainland to Taiwan, eat a cake made of ice, carrot and apple, in Taipei Zoo on Sept 1, 2009. [Xinhua]

Panda experts from the mainland and Taiwan collected sperm from Tuan Tuan, a male panda, and used it to artificially inseminate his female companion, Yuan Yuan, on Wednesday and Thursday.

So far, attempts to have Yuan Yuan impregnated the old fashioned way have failed.

Tuan Tuan's sperm is potent enough. But he seems to show little interest in his ruttish partner, Zhang Hemin, chief of the administrative bureau of Wolong National Natural Reserve in Southwest China's Sichuan province, told China Daily.

Tuan Tuan and Yuan Yuan - whose first or last names mixed together to read Tuan Yuan mean "reunion" in Chinese - have been in Taiwan for more than two years. In 2010, Yuan Yuan went into heat for the first time. But Tuan Tuan was not sexually mature.

Yuan Yuan did not again begin to show obvious signs that she had become ruttish - anxiety, a poor appetite and genital swelling - until recently. This time, nothing physiological prevented Tuan Tuan from completing the task at hand.

His trouble instead was psychological: He could not overcome his indifference to his partner.

"My colleagues from Wolong who are staying in the Taipei Zoo told me Tuan Tuan shows more interest in bamboo roots than a female panda," Zhang said. "Tuan Tuan always has a sound nap after eating his fill."

Taipei Zoo keeps the two pandas in separate cages on purpose.

If they are too familiar with each other, they might begin to feel as if they are a brother-and-sister pair. Such sentiments would not be conducive to natural intercourse and reproduction, said Jason Yeh, the director of the Taipei Zoo.

Even so, the keepers make them swap cages every day, keeping them familiar with their partner's smell in the hopes of increasing their sexual attraction to each other, he said.

Yeh also said zoo keepers have tried to arouse Tuan Tuan's lustfulness by repeatedly having him listen to the recorded noise of a female panda in heat.

Concerned about the pair's chances of reproductive success, the mainland has sent two experts, Huang Yan and Zhou Yingmin, to Taiwan to play Cupid for the panda pair. Each is renowned for the long experience in helping pandas breed.

Huang and Zhou flew to Taipei last Sunday to provide technical assistance as various attempts got under way to induce Tuan Tuan and Yuan Yuan to mate.

The panda species is notoriously reluctant to reproduce. For that reason, it is common for experts with the administrative bureau of Wolong National Natural Reserve to be consulted for breeding advice.

Female pandas go into heat only once a year. To avoid squandering its current rare opportunity, the Taipei Zoo tried to give Tuan Tuan and Yuan Yuan a quiet romantic setting by keeping visitors away from their cages on Wednesday.

If the artificial insemination is successful and Yuan Yuan is impregnated, her cubs will be the first pandas born in Taiwan, according to earlier reports.

Huang Yan said a female panda's pregnancy will usually last for 120 days to 150 days. The shortest panda pregnancy on record lasted for 70 days and the longest for 324 days.

Because pandas have small fetuses, experts often must use ultrasound equipment to ascertain whether a female is pregnant and, to obtain reliable results, must wait 15 days before the birth to conduct the test.