Milwaukee County Zoo officials are hand-raising an Amur tiger cub — an unusual undertaking only done in order to save the cub's life.

Officials had to give special care to the cub named Kashtan after he developed an infection that killed one of his three sisters.

Katie Kuhn, an area supervisor at the zoo, says he recovered about a month later but they didn't know if mother Amba would still recognize him or if she would protect her other cubs because he had been sick.

They now visit him four times a day for feeding and play. They also bring in his two sisters three hours a day.

The zoo's vet, Dr. Vickie Clyde, says his situation helped with early detection of the same infection in sister Bernadette.