A. Definitely this is a concern. Animals may have a decreased appetite in the first 24 hours after surgery, but if he's not eating normally at this point there might be something else going on. Morphine can certainly cause nausea, but the effects of the drug shouldn't last more than 8 hours. Contact the vet who did the surgery to discuss your dog's post-surgical situation and see if he wants to consider medication changes, or a post-op checkup.
Your account has been reactivated.