Are you adding a supplement to your horse’s diet that contains iron? You may want to consider changing it if your horse is overweight, diagnosed with insulin resistance, or suffers from equine Cushing’s disease. Studies have shown a direct correlation between iron intake and insulin levels in the blood, making it an important factor in managing the diet for these horses.
Forages (pasture, hay, hay pellets or cubes) are already high in this mineral; therefore, supplementation is not necessary. Iron deficiency anemia is rare and too much iron can potentially lead to laminitis, as well as create an imbalance with other minerals.
Forages grown from acidic soils will be higher in iron. If you grow your own hay, or can discuss this issue with your hay provider, consider increasing the pH of the soil through lime application. To protect your horse, have your hay analyzed and choose a vitamin/mineral supplement that does not include iron. Calculate the total iron intake in the diet; though an upper tolerable limit for all horses is 500 ppm, it should be far less for sensitive horses. Soaking hay can remove much of the iron, but will also remove other minerals. Balance iron with zinc and copper: iron should not be more than 5 times the level of zinc, and the zinc to copper ratio should range from 3:1 to 5:1.
Juliet M. Getty, PhD, is an independent equine nutritionist with a wide American and international following. Her research-based approach optimizes equine health by aligning physiology and instincts with correct feeding and nutrition practices. Find a world of useful information for the horseperson at www.GettyEquineNutrition.com. Sign up for Getty’s informative, free e-newsletter, Forage for Thought; browse her library of reference articles; search her nutrition forum; and purchase recordings of her educational teleseminars. Reach Getty directly at firstname.lastname@example.org. She is available for private consultations and speaking engagements.