I don't think it's necessary to pre-load for all rides, but I do
believe it is helpful to most horses for hot/humid rides.
A horse is a large animal. Adding a few ounces of salts to his feed
for a day or two leading up to the ride, and giving a syringefull
prior to the start, is not going to cause an imbalance even if he
does not drink. The worst that might happen is that you'll pull a
little water out of his bloodstream into his gut early on, but it's
still inside the horse ready to be reabsorbed when needed.
Giving electrolytes will make most horses thirsty and encourage
drinking to some extent. Try it on yourself -- lick a handfull of
salt and see if you don't feel like drinking some water soon
afterwards.
As in all cases, horses are individuals and there will be exceptions
-- so try it at home first, using a hot/humid training weekend; and
when you first try it for a ride, go easy on the quantity and watch
the results. If everything goes OK, use more the next time.
--Joe Long Rainbow Connection Arabians PC/LAN Manager home of Kahlil Khai Calhoun Community College AERC Hall of Fame horse jlong@hiwaay.net 11,475 miles completed