You should wait about an hour generally but I like to wait 1.5 if im going to feed after a meal so they wont risk colicing.
If I ride in the morning I ride before I feed and my horse can suck it up and deal with being hungry a tad longer. That being said morning rides are around 5 or 6am and feeding is around 6 or 7am depending. It changes daily based on my friends schedule. Posted via Mobile Device