The other ultrasound is done through her abdominal wall to check on her 200-pound calf, which seems to stir with the vibrations. "She - he or she, the calf - seems healthy, and quite active," Bronson said.
Felix's veterinarians have also drawn blood regularly to build up a store of frozen plasma. The blood plasma is rich in antibodies specific to the zoo's environment, Bronson said.
Normally, the calf would get its initial dose of antibodies from colostrum - the thick, yellowish substance in a mammal's early milk. But if Felix's calf does not nurse right away, the plasma will be provided by mouth or IV, to strengthen its immunity.
"Hopefully, we won't need it at all," Bronson said. "It depends on how the calf is doing."
The other two, old female elephants at the zoo - Dolly and Anna - are also trained to give blood, and can be used in the event that whole-blood transfusions are needed.
For now, Felix is behaving normally. A brownish-red from the red Maryland dirt she dusts herself with, she moves easily from barn to yard these days with no evident discomfort. But that will change.
"You'll see a number of behavioral changes" when labor begins, McClure said. There's a general restlessness. She might slap her tail, stretch her rear legs or toss dust onto her belly - all likely in response to uterine contractions.
Milk might also begin to seep from her mammary glands. And in time, her water will break.
When delivery appears imminent, zoo officials will summon two expert advisers to her side - Dr. Dennis Schmitt of Missouri State University and Scott Riddle from the Riddle Center. Dolly and Anna will also be close by, within easy view of the drama, as they would be in the wild.
When Felix is ready - the whole process can take 20 minutes or 24 hours - she'll drop the calf onto the wood chips and absorbent wheat bran that the zoo has provided in the barn. Keepers and vets will then move the calf to a safe spot, still within Felix's view. They'll check its vital signs, mouth, trunk and eyes, towel it off and take a blood sample.
Back in her mother's care, the infant should be on its feet in less than 30 minutes, and nursing within the first few hours of life. The vets will also collect and examine the placenta to be sure it all has been expelled and there's no risk of infection.
"Otherwise, Felix will be taking care of everything," Bronson said.
How quickly mother and baby will be out on public view, her keepers can't say. That will depend on how mother and infant do. Meantime, zoo officials hope to take pictures and get them to the public as soon as possible.
frank.roylance@baltsun.com
