Quiessence is a magnesium-based feed supplement that can benefit nervous, high-strung, irritable or sore horses. Studies show additional benefit to horses with thick, cresty necks that were prone to founder, making them easier to manage, ride and handle. Feed 1 oz per 250 lbs. body weight daily until improvement is evident. Feed 1/2 oz per 250 lbs.daily for maintenance. Pellets.