Yes, if the baytril is given orally it can make the cat not want to eat. It can be so severe that sometimes another antibiotic has to be used. Is there another vet in the practice taking over the cases while yours is on vacation? Or are they referring to another practice? If you can, make sure to call tomorrow and see if they want to change the antibiotic. At the minimum, I usually take them off it for a day or two and maybe try again. Most of the time, though, if the baytril causes them to lose their appetite, I just try a different antibiotic. THere are several that can be used instead of baytril. I would skip this evening's dose, and call the vet in the morning.