PITTSBURGH -- Veterinarians at the Pittsburgh Zoo and PPG Aquarium continue to care for a newborn tiger cub rejected by his mother.

Toma gave birth to the cub on Sunday and then stopped caring for it.

Since then, zookeepers have been bottle feeding the cub every three hours.

Zoo officials said a shortage of milk may be the reason the mother, Toma, is rejecting the newborn.

Vets are treating her with a drug to initiate nursing behavior.