Horse Feed Tag Mathematics

It takes some time and math skills to properly understand how the guaranteed analysis relates to what your horse is actually taking in every day!

It takes some time and math skills to properly understand how the guaranteed analysis relates to what your horse is actually taking in every day!

We often receive questions from horse owners, wondering what the various units of measure on horse feed tags mean, and how they can use those units to figure out what their horse is consuming…and wondering why in the world they have to be so confusing, too!

In short, feed companies use the units of measurements on nutrients that we do, because we are required to. Why? Because horse feeds and other livestock feeds are labeled as required by AAFCO (American Association of Feed Control Officials) and the various state Feed Control regulations.  These regulatory bodies establish the units which are to be used for each nutrient in tag guarantees.

To break it down, there are 4 common units used on feed tags.  To help you understand them all, here’s a quick overview of how they work, along with examples of how to do the appropriate math:

Protein, amino acids, fat, fiber and macro minerals (calcium, phosphorus, magnesium and potassium) are listed as a % minimum or maximum.

  • To calculate the amount supplied per pound, you can convert % to a decimal fraction by moving the decimal point 2 places to the left, then multiply by the pounds fed.
  • As a horse’s daily intake requirements are sometimes given in grams, we can convert those pounds of intake to grams as well.
    • For those of us that are mathematically challenged, a quick Google search of “pounds to grams” will provide a handy conversion calculator!

Example:

  • A feed that is 14% protein would contain 1 lb x 0.14 = 0.14 lb of protein in 1 pound of feed.
    • If you want to measure in ounces, there are 16 ounces per pound, so the same pound of feed would contain 0.14 x 16 = 2.24 ounces of protein.
    • If the requirements are given in grams, we know that there are 453.6 grams per pound, so the feed would contain 453.6 x 0.14 = 63.5 grams of protein per pound of feed.
  • Feeding 5 lbs of this feed per day, results in feeding 0.7 lbs, or 11.2 ounces, or 317.5 grams, of protein per day.

Trace minerals (copper, zinc, manganese and selenium) are expressed as “ppm” or parts per million.

  • One part per million is the same as one milligrams per kilogram.
  • 1 kilogram = 2.2 pounds.

Example:

  • Premium horse feeds are commonly tagged at 0.6 ppm selenium.
  • This is 0.6 mg/kg of feed. This equals 0.273 mg per pound of feed.
  • 0.6 mg/kg divided by 2.2 kg/lb. = 0.273 mg per pound of feed
  • Feeding 5 lbs of this feed per day, results in feeding 1.365 mg per day of selenium.

Vitamins A, D and E are expressed in IU/lb.

  • An IU is an International Unit and is based on the effectiveness of a particular vitamin.
  • There are some rather complicated conversions of different Vitamin sources to International Units, which is why animal requirements are given in International Units, so no further conversion is needed.

Example:

  • A feed that lists 100 IU/lb of Vitamin E, fed at 5 lbs per day, provides 500 IU’s per day.

Vitamin C (or Ascorbic acid) and Biotin are normally expressed as mg/lb or milligrams per pound.

  • Usually only tagged on senior horse feeds.
  • Requirements are in mg of intake per day, so no further conversion is needed.

Example:

  • A feed that lists 75 mg/lb of Vitamin C, fed at 5 lbs per day, provides 375 mg per day.

Still confused?  Don’t worry about it. Just leave us your questions in the comments section below, and we’ll be happy to help you out!

11 thoughts on “Horse Feed Tag Mathematics

  1. I am in the process of transitioning my horse to Nutrena – I’m starting with the Safe Choice, but I have a bit different problem in deciding on the right feed.
    I have a 16hh 15 year old Shire/TB that I event at Prelim. I need a good quality feed to provide good energy and muscle rebuild qualities but I don’t need weight gain . . . the Shire half looks after that 😉
    Last year the season ended with her just a little more tired than usual. Which food in your line up would you suggest? She is starting back into work after a couple winter months off in the pasture. She is hay feed through the winter, but on pasture in the summer – in what we call our jingle pasture with less grass for part of the day and regular pasture for some of the day.

    • Hi Laurie, Great question. For her “off season” where you simply want to get quality nutrition without the calories in to her, we would suggest Empower Balance as a great product to sustain her condition and health, without adding weight. As she comes in to the eventing season, you would then have a couple options – continue the Empower Balance and add Empower Boost (high fat rice bran to provide the needed calories for her activity) on top of it, or you could switch to a product such as SafeChoice Original and feed at the low end of the suggested feeding range for her size & activity level. Both would provide the calories and nutrition she needs, while controlling her weight!
      Thank you ~ Roy J.

    • We formulate to a magnesium minimum in our formulation system considering the nutrient content of all ingredients. Where there is adequate naturally occurring magnesium from ingredients such as wheat midds (0.42% magnesium), alfalfa (0.26% magnesium) and other ingredients, we do not need to add magnesium sulfate or magnesium oxide as a source of added magnesium and the magnesium sulfate or magnesium oxide would not appear on the tag.

      When there is not adequate naturally occurring magnesium from ingredients, we add magnesium sulfate or magnesium oxide to meet our formulation specification and the source of added magnesium would then appear on the tag.

      Thank you ~ Roy

    • Hello Diana, Thank you for contacting us. Yes, we actually use organic complexed trace minerals in all our premium feeds, which includes the SafeChoice, ProForce, Empower, Pennfields, and Vitality families of products. Organic complexed trace minerals are a step up from chelated trace minerals. In chelated trace minerals, the mineral molecules are tied to general amino acids. In organic complexed trace minerals, the mineral molecule is tied to the specific amino acid that best helps that mineral absorb. For example, zinc is specifically tied to methionine. You can read more here: http://www.nutrenaworld.com/knowledge-center/horse/horse-nutrition/functional-ingredients/trace-minerals/index.jsp.

      Thank you ~ Gina T.

  2. Dear Roy, Eureka! I found you! I am a sheep owner, but your math explanation is great for evaluating mineral/salt mixes for all livestock owners. Small sheep flock owners who live in areas where sheep are not commonly raised have little to no vet or extension advisors available. Small ruminants are really complex in their needs. Thanks for addressing this important aspect of understanding nutritional science in agriculture.

  3. Hello. I am introducing my 34 year old mare to Empower. Before doing so, I need to determine if she will be getting too much selenium from the Empower and other feed I am using. I hope you can help me determine (1) a safe amount of Empower to feed and (2) if I can eliminate the MiniVite Light. I am currently feeding 5 cups (twice per day) of Dynasty Pro and 1 cup of MiniVite Light (twice per day). Can you help me convert the ppm to pounds as well as suggest if I can eliminate the MiniVite Light? Thank you in advance!

    • Hi Gloria,
      If this horse is in good body condition and health, I would recommend simplifying the diet and just providing the recommended pounds per day of Empower Balance, and good quality forage, salt and water, assuming the dental health of your horse is adequate to graze/chew forage.

      It would be helpful to know how much 10 cups of Dynasty Pro actually weights (pounds or kg). If you are feeding this product mix to get extra calories in, I would recommend SafeChoice Original or SafeChoice Senior as an alternative to the Empower Balance. If the horse is in good body condition and can consume enough good quality forage, the Empower Balance is fine.

      If Empower Balance is fed per directions, an additional vitamin/mineral supplement should not be required. Water and salt should be available free choice at all times.

      Best of luck!

  4. retired racehorse 6yrs old about to be started on Nutrena Empower Boost High-Fat Rice Bran Horse Supplement. It says feed 1lb per day of the food and we have a 3 quart scooper. How many quarts would he get a day?

    • Hi Emily,
      Thanks for reaching out! So if you have a 3 qt scoop, that holds about 3 lbs. So knowing how much your horse weighs, activity level and age will help you best determine what rate to feed Empower Boost. We have a great feed rate estimator tool on our website that can be found here: . Scroll to below the Guaranteed Analysis, and you can enter the info specific to your horse to get a recommended feeding rate. Additionally, here is a previous article we posted about feeding scoops and how much they hold, that you may find helpful! .

      Best of luck!
      Robyn

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