Question: My Peruvian mare just tested positive for IR and I highly suspect it was triggered by a high iron level in the hay she has had exclusively over the past one year (tested at 151 ppm/ 69 mg/lb).I am no longer feeding that hay, but also suspect water level of iron may be around 0.5 ppm. What do you suggest to remove the iron overload presumably already in her system?

Dr. Kellon: While 151 ppm is more than she needs, it's actually below the average of 198 ppm found in the DairyOne database containing over 46,000 samples of grass hay.  There is evidence that many IR horses are iron overloaded and high iron burden may be a complicating factor but the actual cause of IR is genetics and Peruvians are known to be at risk. 

Going forward, you want to keep everything in her diet below 10% sugar and starch combined. For the iron issue, maintaining an iron:copper:zinc ratio no higher than 4:1:3 will help prevent further overload and eventually lead to her using up some of the stored iron.
For an accurate picture of her body iron levels you need to send blood for serum iron, iron binding capacity and ferritin. Only Kansas State can run these tests and there are strict sample handling guidelines: