I send out Oban in my start-up Package as an odor neutralizer. It could be that the animal distributed its pee widely over the surface area of the rug. You might want to invest in a black light which will help you to observe urine deposits. You can find these at the various pet supply houses such as Petsmart, or at a well-stocked janitorial products outlet. When I come upon a customer with a seriously pet-impacted rug, I will often suggest that they have it sent out for a full immersion cleaning, which will give them the best shot at having all of the odor removed. You can establish an arrangement with one or more such facilities in your area, and receive a referral fee from them for every rug you send them.