What is the ruling on donating to an animal welfare society, raising cats at home, and feeding and treating stray cats out of compassion?

There is no objection to donating to organizations whose activities do not involve a Sharia (definition)-prohibited matter. There is reward and recompense for the donor in this if they have a good intention, for kindness to animals is religiously مطلوب (required/desired). Nevertheless, it is better to direct donations to the poor among Muslims, especially those in need in Palestine and other parts of the world.