WASHINGTON - The US National Zoo's panda team gave a newly born panda cub its first neonatal exam on Sunday morning, and found it healthy, said the zoo authorities.

This is the first exam done by the panda team after the cub was born Friday afternoon.

"The cub is robust, fully formed, and is bright, healthy shade of pink," said the zoo in a statement.

The newly born baby panda weighs 137 grams. Its heart rate is steady, and veterinarians were able to hear breathing sounds from both lungs.

"All signs are that we have a very healthy, active, vibrant cub," said the zoo.

The cub was born to female giant panda Mei Xiang at 5:32 pm Friday. Mei Xiang also gave birth to a second but stillborn cub late Saturday, the zoo announced Saturday night.

The National Zoo now houses Mei Xiang and Tian Tian, a pair of giant pandas on loan from China. Mei Xiang gave birth to her first cub Tai Shan in 2005, which now lives in China. She also gave birth to a female cub last September, which died a week later due to liver failure caused by lung problems.

The zoo authorities have invited panda keepers and experts at the China Conservation and Research Center for the Giant Panda in Wolong, Sichuan province, to support the zoo's panda team.

Sources from the zoo said the panda team would continue to perform more health checkups every few days during the next week.

Further test and analysis will also be conducted to identify the cub's sex or its paternity in two or three weeks.

Mei Xiang was artificially inseminated twice in March after natural breeding attempts with Tian Tian were unsuccessful. US and Chinese veterinarians used semen collected from both Tian Tian and Gao Gao, another male giant panda kept at the San Diego Zoo, California.