It is normal for a cat to purr when it steps on the milk, indicating that the cat is in a happy and relaxed mood. Cat stepping on milk is an instinctive reaction. When a cat is just born, it will explore the mother cat's nipples, step on the milk to stimulate the mother's breasts to secrete more milk, and make purring sounds to communicate to the mother cat. A very healthy sign.

Tip:

Cats will also purr when they are sick and uncomfortable. They use this sound to soothe themselves. If your cat purrs like this anytime and anywhere, it means your cat may have a respiratory infection. When the owner strokes and massages the cat, the cat will purr because it feels comfortable.