Please DO NOT fast your rabbit! The staff may tell you this, but directly ask the vet. If they tell you that I might think twice about how much they know about rabbits. Buns can not vomit, so they are not at risk for aspirating fluids. They are much more likely to go into stasis or even not survive the surgery if they are fasted. Food may be taken away 30 minutes before so there's nothing in their mouth. You will want to send pellets and hay they are familiar with so they are more apt to eat. You will also want to send some favorites (carrots, cilantro, raisins etc) to tempt your rabbit to eat after it wakes up.
You may want to do pre-op blood work, but that is up to you and the vet. A lot depends on the age and condition of the rabbit. You will also probably want to discuss pain control. It is vital to ensure the rabbit is not in pain after the procedure. You will want to take home medication such as meticam to help them be comfortable. It's a major abdominal surgery so you would want pain meds too. The biggest problem is stasis because they will not eat if in pain.
Other than that there's not much to be done before. You will want to keep her as quiet as possible for a while after. It can be a real challenge, but no jumping on or off anything for a week minimal. Watch for redness, swelling, or licking of the incision. If the rabbit is sitting hunched in the corner looking miserable then she is in pain and needs more medication, discuss the dose with the vet.
Hope this helps. My Sophie was getting done tomorrow, but it got bumped to Monday.
