The meaning of cat tattoo is sacred and giving love. Cats are magical species. When you think the world is too cold and hard, cats can make you feel warm and soft. When you feel that you have been given love all these years and can't return it, cats make you feel how wonderful it is to give love.
I don't remember whether Nietzsche said it. He said that life is meaningless, but the process of finding meaning is meaningful. Similarly, raising a cat itself is meaningless, but the process of finding meaning itself is meaningful.