If any of ours have been sedated, whether it be sedaline, ACP tablets or by IV (SediVet/Dolorex usually) then they don't have anything to eat until they are pretty much out of influence of it. Having seen the blood come out of a mouth from a doped up horse that bit it's tongue eating hay, I'd rather not risk it. It wasn't pretty and the horse was rather sore for a few days.
there is an increased risk of choke/mouth injury from eating whilst sedated and advise from vets is not to give any feed stuff/forage till sedation has worn off