Magnesium is involved in over 250 separate body reactions in the horse. In many cases it serves to naturally balance the actions of calcium. Calcium has an excitatory effect on muscle and nervous system tissues. Magnesium is often supplemented because it helps support normal insulin action and helps keep blood vessels normally dilated. A magnesium supplement may be indicated for both absolute and relative deficiencies in horses. An absolute deficiency is when the total magnesium intake is below the minimum recommended for the horse. A relative deficiency is when high levels of calcium or phosphorus may interfere with magnesium absorption. Horses on high intakes of fat may also benefit from a magnesium supplement since fat and magnesium combine in the intestinal tract to form nonabsorbable soaps. The dosage of magnesium supplement is ideally based first on analysis of the diet but knowledge of regional mineral profiles in forages can also be used. In most areas a dose of 5000 to 10,000 mg of magnesium (equivalent to 1.5 to 3 generous scoops of Bioplex Magnesium) is a good starting point. Magnesium oxide has good bioavailability in horses. It is the most concentrated magnesium source meaning you can feed less than with other forms. This makes it more economical and less likely to be refused by the horse.

• Feed at the rate of one scoop daily or as directed by your veterinarian or nutritionist.