Original: Knut's need for round-the-clock care required that DÃ rflein not only sleep on a mattress next to Knut's sleeping crate at night, but also play with, bathe, and feed the cub daily.
Simplified: DÃ rflein had to sleep on a mattress next to the cub at night because Knut needed care. DÃ rflein also had to play with, bathe, and feed the cub every day.