pace in endurance

["guest@endurance.net" <guest@endurance.net>]

April Hammer steele@mwonline.net
I have competed in competetive distance events for the past 3 years, completing several 50s.  My horse maintains well, and when shoed correctly is sound.  My question is: When I begin to enter endurance events, how do I choose a pace?  I condition mostly at a trot with intervals of loping, but not for long periods of time. When I see the completion times in endurance events, I am often amazed. Am I just not trusting my horse?  Should I ask for a little more?  I know he's ready for more, but I seem to be the one holdng us back.  Help!!!  I do have a heart monitor and understand cardiac recovery. I also understand that I need to watch him metabolically and make sure he's eating.  Are there any other clues, on the trail, to warn me that I may be pushing too hard?  Thanks for the advice.  April ps. I live in central Illinois, so trail is not too hilly or tough (compared to Mountains)