For the Health of It
Do the Math for Improved Equine Nutrition
By Juliet M. Getty Ph.D.
Reading a hay analysis report or puzzling over the
ingredients in feed or supplements can be a chore, yet
when considering particular elements—selenium, for
example—some minor math can make a major differ-
ence to your horse’s health.
Formulas to remember when working with ppm:
• Convert lbs to kg: lbs x 0.454 = kg
• Calculate to find mg: kg X ppm (or mg/kg) = mg
What about percentages?
The concentration of many nutrients can be present-
ed as a percentage instead of ppm. Protein, fat, carbo-
hydrates, and major minerals are measured as grams,
rather than mg.
Let’s say you would like to know the number of
grams of protein in 20 lbs of your horse’s hay. It con-
tains 8% crude protein.
First step, convert lbs to grams: 20 lbs hay X 454 g/lb
= 9080 grams.
Next, multiply the grams of hay by the percentage
(move the decimal point left two spaces): 9080 lbs of
hay X .08 = 726.4 grams of protein.
Formulas to remember when working with percentages:
• Convert lbs to grams: lbs x 454 = grams
• Calculate to find grams: grams X percentage
(move left two decimals) = grams
Feed tags and hay analyses often list ingredients as
“ppm” or parts per million. Does this confuse you?
You aren’t alone. The best way to think of ppm is as
milligrams per kilogram (mg/kg) of feed (since a mg is
a one millionth “part” of a kg). Therefore, wh en using
mg/kg, all you have to do is make sure you’re dealing
with kg of feed (instead of lbs) before doing your cal-
culations.
Consider this example: Your hay contains 0.2 ppm
(mg/kg) of selenium. How many mg of selenium does
20 lbs of hay contain?
First, you need to convert the lbs to kg. Since there
are 0.454 kg in one lb, make the conversion by mul-
tiplying lbs by 0.454. So, 20 lbs multiplied by 0.454
equals 9.08 kg (20 x 0.454 = 9.08).
Now that you have your hay measure in kgs, you’re
ready to calculate mg of selenium. Multiply 9.08 kg of
hay by 0.2 ppm (or mg/kg) (9.08 x 0.2 = 1.816). That
rounds to 1.8 mg of selenium in your 20 lbs of hay.
6 • Walking On
Juliet M. Getty, Ph.D. is an independent equine nutritionist with a wide U.S.
and international following. Her research-based approach optimizes equine
health by aligning physiology and instincts with correct feeding and nutrition
practices. Dr. Getty’s goal is to empower the horseperson with the confidence
and knowledge to provide the best nutrition for his or her horse’s needs.
Dr. Getty’s fundamental resource book, Feed Your Horse Like a Horse,
is available in paperback as well as in hardcover, searchable CD and Kindle
versions. All except the Kindle version are available at www.GettyEquine-
Nutrition.com -- buy the book there and have it inscribed by the author.
Print and Kindle versions are also available at Amazon (www.Amazon.
com); find print versions at other online retail bookstores. The seven indi-
vidual volumes in Dr. Getty’s topic-centered “Spotlight on Equine Nutri-
tion” series are available with special package pricing at her website, and
also at Amazon in print and Kindle versions. Dr. Getty’s books make ideal
gifts for equestrians!
Find a world of useful information for the horseperson at www.Get-
tyEquineNutrition.com: Sign up for Dr. Getty’s informative, free e-news-
letter, Forage for Thought; browse her library of reference articles; search
her nutrition forum archives; and purchase recordings of her educational
teleseminars and interviews. Find top-quality supplements, feeders, and
other equine-related items, at her online Free Shipping Supplement Store[i].
Reach Dr. Getty directly at [email protected].
[i] http://horsesupplements.gettyequinenutrition.biz