The halachos regarding human waste do not apply to the droppings of a horse or dog unless the droppings have a foul smell. Therefore, one may recite a Davar Shebikudusha in the presence of the droppings of a horse or dog that don’t have a foul smell. However, the droppings of a cat do have the same halachos as human waste, and one should distance themselves if they see or smell it. One does not need to always be concerned that there are cat droppings around because cats generally bury their droppings.