Deciphering Labels

Whether it’s a bag of feed or a supplement,  a complaint that comes up over and over again is how difficult it is to read label information.  What exactly do those numbers mean?


From the perspective of an owner, trainer or barn manager there are two distinct issues.  One is knowing what you are looking for.  “It’s in there” is not good enough.  You have to know the target amounts for vitamins, minerals, herbs, etc. to know if the product meets your needs.  These dosages also vary by weight and use of the horse, any problems you are trying to help and the amounts already present in the base diet.

If you do not know these target amounts, it doesn’t matter how easy to read the label might be.  You need to get educated to evaluate these products.  Consult a nutritionist or veterinarian well versed in nutrition, read articles, take classes.  Once you know what levels you are looking for you can begin to evaluate products and compare them with others.

To give you some general guidelines, the following amounts are the recommended minimum daily intake for an 1100 pound horse in light work:  Calcium 30 g, phosphorus 18 g, magnesium 9.5 g, potassium 28.5 g, sodium 13.9 g, chloride 46.6 g, copper 100 mg, zinc 400 mg, manganese 400 mg, iodine 3.5 mg, selenium 1 mg.  Note: g = grams, mg = milligrams.

The second issue is deciphering the information on the labels.  Using minerals as an example, daily requirements are in grams (calcium, phosphorus, magnesium, sodium, chloride, potassium) or in milligrams (selenium, iodine, copper, zinc, manganese).  The most customer friendly companies will provide you with these amounts on a per dose basis.  Unfortunately, this is the exception rather than the rule.

The way ingredients are listed on a label is partially dictated by regulations.  Minerals needed in gram amounts are called major minerals and are listed on the ingredients list as a percentage/%.  Minerals needed in milligram (mg) amounts, called trace minerals, are listed as ppm, parts per million.  To confuse things further, suggested dosages are commonly give in ounces so you have to convert back from that to the metric system unless the company provides this information on a per dose basis.

If you’re ready to throw up your hands and give up now, don’t.  Bear with me here.   An ounce is 28.4 grams.   If a product has 10% calcium, an ounce will provide 0.1 x 28.4 = 2.84 grams of calcium, compared to the 30 gram requirement for the horse above.  On the trace mineral front, a level of say 2000 ppm for zinc might look impressive – until you do the math.  An ounce is 28.4 g, or 0.284 kilograms.  To calculate zinc content in an ounce, it’s 0.284 x 2000 = 56.8, compared to the 400 mg minimum requirement.

Doing the math is tedious but it gets easier the more you do.  The effort is well worth it to see exactly what you are paying for.

Eleanor M Kellon, VMD



About Dr. Kellon

Graduate of University of Pennsylvania Veterinary School. Owner of Equine Nutritional Solutions,, industry and private nutritional consultations, online nutritional courses. Staff Veterinary Expert at Uckele Health and Nutrition.
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