Thehorse.com - Full Article
By Karen Briggs
Aug 14, 2014
Grains, the “traditional” feed for high-level physical activity, supply carbohydrates and starches—versatile energy substrates that fuel the horse’s muscles for athletic endeavors of all kinds. Fat is also an energy substrate which, while not as flexible as carbohydrates in terms of the types of activities it can fuel, might in many ways help the horse’s body use itself with more efficiency and less fatigue.
Two main energy pathways fuel a horse’s muscle cells to do work. (A third pathway, called “anaerobic alactic” metabolism, is a “startup” system that only comes into play for extremely short bursts.) The predominant energy pathway is aerobic metabolism, which the muscles use whenever they can, for all low-intensity and endurance activities, especially those requiring a continuous effort of longer than two minutes (and possibly lasting many hours)...
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