Liver failure caused by lung problem led to death of giant panda cub in Washington's National Zoo, officials said Thursday.
Chief veterinarian Suzan Murray said a necropsy on the female cub, which was found dead on Sept. 23, seven days after its birth, determined the liver failure was caused by insufficient supply of oxygen.
Murray said the cub lungs were poorly developed, likely causing her to have insufficient oxygen, and hence liver necrosis. The necropsy showed that the week-old female cub had fluid in her abdomen and her liver was hard in places.
The zoo said there were no signs of internal or external trauma, and that lung and liver damage ultimately caused the cub's death. The mortality rate for pandas in their first year in captivity is estimated to be 26 percent for males and 20 percent for females.
The giant panda cub was born in the zoo on September 16. Her mother Mei Xiang, according to the zoo, is "almost completely back to her old self." The zoo said Mei Xiang's hormones have returned to normal levels, as she is choosing to go outside in the mornings. In the afternoons she can usually be found napping on her indoor rockwork. Her appetite has also returned.
Mei Xiang gave birth to her first cub, Tai Shan, in 2005. Tai Shan now lives in China. The National Zoo now houses Mei Xiang and Tian Tian, a pair of giant pandas on loan from China.