First and most important. DO NOT fast bun prior to surgery. Red flag if the actual vet gives this instruction. DO bring some of your buns food to the vet pre surgery, to leave for them to give following surgery.
Pain meds for 2-5 days. I prefer meloxicam, at least at 1mg/kg/day dose, split into twice daily dosing, for adequate pain control and help reduce swelling.
https://www.vgr1.com/metacam/
Make sure bun is staying warm enough as they often get chilled after anesthesia, and a cold bun is less inclined to eat. I'll check by feeling the ears (cold ears will usually mean a cooler body temp), then provide a rabbit safe heating pack/pad.
Make sure bun is eating mostly normal by 24 hours from the time bun for sure last ate well. Usually need to be eating fairly well by the next morning following surgery. Not eating for more than 12-24 hours is usually considered an emergency situation with rabbits. If not eating adequate amounts by the next morning, or you have any concerns something is wrong with your bun at any time, contact vet. You'll need syringe feeding mix (eg critical care mix) and syringe feeding instructions, and possibly meds at a minimum to keep your buns gut functioning.
I've had the best luck getting my buns eating again by offering lots of my buns usual leafy greens (romaine, parsley, cilantro, carrot greens, etc), and always grass hay available (refreshed with new handfuls). Veggies and greens also help hydrate bun. A little bit of your buns usual fruit/treats, but should be limited so gut bacteria isn't upset.
Limit activity (no running or hopping up on things) for usually 5-7 days for the males. May have to reduce buns area if getting too rambunctious.
Spaying and neutering rabbits
https://web.as.miami.edu/hare/opcare.html
