Measuring Minerals in Horse Diets

Minerals are generally listed in two ways on a feed tag guaranteed analysis. 

  1. Macro minerals, or those needed in larger quantities, are expressed as a percentage. They include calcium, phosphorus, sodium, chlorine, potassium, magnesium, and sulfur. 
  2. Micro minerals, or those needed in smaller amounts, are expressed as “parts per million” which is what the “ppm” on the tag stands for.  Occasionally a feed tag will list these in “mg/kg”, which converts directly to ppm – 1 ppm is equal to 1 mg/kg.  These minerals include selenium, iodine, copper, zinc, manganese, and iron.

When analyzing a feeding program, it is of great importance to make sure that the same units of measurement are being used.  Often times, test results for a hay sample that has been analyzed will not be expressed in the same unit of measure as the nutrients guaranteed on a bag of feed.  So, in order to know what the entire diet is providing, make sure you are comparing apples to apples!