D.C. zoo will try again to exam newborn panda cub WASHINGTON Caretakers at Washington's National Zoo hope to get the first close look at a newborn panda cub during a weekend exam. During the checkup, officials will try to listen to the cub's heart and lungs, record its weight and collect a DNA sample. The minutes-long health assessment was initially planned for Saturday, but mom Mei Xiang didn't give keepers an opportunity to take her cub, which was born Friday evening and is about the size of a stick of butter. Brandie Smith, the zoo's curator of mammals, says she and others are "cautiously optimistic" about this cub's health. She compared the planned exam to a race car pit stop, a fast and highly choreographed checkup before reuniting mom and cub. The cub is the 15-year-old panda's third. The cub she gave birth to last year died after just six days. That cub's lungs hadn't fully developed and likely weren't sending enough oxygen to its liver. Mei Xiang's first cub, a male named Tai Shan, was born in 2005. An early exam at the zoo is a change from last year, and staff members have made several other changes in preparation for another cub. Mei Xiang's den has been altered to allow keepers to get closer to her, and the zoo also invited a panda expert from China who specializes in newborns to help out. Two of the zoo's panda keepers have also recently spent time in China learning more about examining newborns. Zookeepers made two attempts at examining the cub Saturday, but Mei Xiang was cradling the cub and officials were unable to take it for a closer examination, zoo spokeswoman Pamela Baker-Masson said. They planned to try again Sunday. Information collected during the exam will serve as a baseline for future exams. And the DNA sample, either from a swab of the cub's mouth or feces, will be used to determine the cub's father. Mei Xiang was artificially inseminated both with sperm from the zoo's male panda, Tian Tian, as well as a male panda at the San Diego zoo, Gao Gao. Visitors to the zoo Saturday said they were excited about another panda cub. Melissa Schmechel of Alexandria, Va., said she spent about 30 minutes Friday watching the zoo's online panda camera after it was announced on Facebook and Twitter that Mei Xiang had gone into labor. She said she and her family had made plans to visit the zoo last year after the birth of Mei Xiang's second cub and were sad when it died. "Hopefully this will have a better outcome," she said as her 11-year-old daughter, Laura, hugged a newly purchased stuffed panda.