Calculating Non-Conventional forms of Exercise

Hi, my name is Lacy, and I'm a competitive horse rider and Three-day eventer in Texas. I have been riding horses for over twenty years now, I'm a pretty fit person, but much of my life has been spent eating whatever I darned well pleased because my metabolism was always off the charts. Well... As the saying goes, good things never last.

Now that I am getting nearer to an age when metabolism naturally slows down, I'm taking better care to control my intake based on the level of energy I expound each day. I do ride approximately Six days per week, with varying levels of intensity and activity from one day to another. This can include: Walking, posting/sitting trot, and cantering for ten minutes at a time without break; conditioning exercises, jumping exercises, no stirrups work, carrying jump poles and standards, rigorous grooming/bathing, stall mucking, hauling buckets, etc.

And while Horse Riding is actually found in the Exercise database, you can bet your britches it does not include all of That!

So here is my question: How can I best break down my activities to most accurately calculate the amount of calories burned on any given day?

Keep in mind that, since this is labor I have been doing for two decades, my body has developed the specific muscles acclimated to this kind of work. I may not be burning as many calories as it seems, and I'm not sure how to compensate for that situation.

If anyone could provide assistance in tabulating non-conventional forms of exercise (short of getting a fancy watch), I would greatly appreciate it!

Lacy