Dog with Urinary Problems/ Any Vets Out There? DVM?

I've seen some pups get UTIs after surgery - I think it is just from the stress of going through surgery and anesthesia and their immune systems taking a hit. Baytril is an antibiotic (brand name...the drug name is enrofloxacin) and is generally very good for treating UTIs. But all antibiotics take time and sometimes they can have other issues that cause similar signs without it actually being a UTI. If she's not showing any improvement by Saturday, I would call your vet and see what else they recommend.

Edited to add: I don't recommend steroids like prednisone for UTIs - they inhibit healing (not a good idea after surgery!) and a side effect is for the pet to drink and pee more! If your dog is uncomfortable and needs something for pain, a non-steroidal anti-inflammatory, like Rimadyl or Deramaxx, would be more appropriate. Hopefully she is on some pain meds already because of being spayed.

Same thing happened to my dog when he was fixed. He ended up needing a second antibiotic because the 1st one didn't clear it. I saw a difference within 24hrs of him starting the next round. I would call in the am if there is no improvement. Poor little guy :(

I'm not a DVM but I was a vet tech for about 11 years.
Yes this can be a common problem after surgery. It will take more than three doses of Baytril till you see some improvement. It is a common broad spectrum antibiotic that is very good for urinary infections.Provide plenty of water for her and she should be better soon. Keep your vet posted on her progress or lack of but I think with some more time she should be fine. Sometimes a steroid can be used for the inflammation but will not be used unless really needed.
Best Regards,
C.