That's revolting. We had a similar issue (filthy floors, was noted in report but nothing was done about it), and the agent repeatedly ignored us. We had to threaten to take it to the RTA before they did anything. That might be an option you can look into if they ignore you...I honestly wouldn't invest money into having it cleaned yourself because a) it's not your responsibility and b) Dog urine? I doubt you will be able to shift the smell.
You will see a clause in your lease agreement specifying that the property must be clean to a hygienic standard upon moving in, so they are letting you down on their part of the agreement and you have every right to take further action.