Hello My Dear Friend,
My rescued beaglette does the same. She also has the same back story and yucky penchant for poop. Here’s what I do.. clean up waste asap (yes, honestly I am not the best at this as I recommend others to be). I also use a clicker or beeper to break her of it while she is doing it. Some non-vocal (she doesnt really want to listen to me anyway in the fever of the fervor to eat anything) cue to say “HEY! YES! I mean you need to stop that!” It takes a while but all of my other dogs have grown out of it.. It takes time and patience like everything else in life. Be with her at all times outside. Use a leash if you can to correct her at exactly the moment she goes for it, or use a whistle to get her attention,,, try to only use it for the absolute dire corrections so it doesnt get as monotonous as our voices have.
Let me know what works for you guys.
This is a discussion t9 have with your vet. I’m sorry… I know you probably want a more direct answer. Your vet knows your cat and your situation. They are the best person to sit down with and have this conversation. They can prescribe a routine suited for your cat including treatment and pain management. Best of luck to you.
I age never seem a case that was too big for surgery. I’m not saying it isn’t possible. I just haven’t seen it. Ask for a second opinion or see a surgeon. I doubt this will be responsive to pred. Surgery is the best option. In my opinion. Good luck. Ps. Also have her spayed if she isn’t already