Alfalfa and the IR Horse

The horse hasn’t been born that doesn’t love alfalfa.  Although it poses some balancing challenges, alfalfa can be a valuable addition to the diet.  However, for reasons that are not yet explained alfalfa can cause flares of laminitis pain in some IR horses.


I have recently been asked about some information floating around the internet that claims to explain why this happens.  The statements were that the carbon skeletons of amino acids and/or propionate used as a preservative on alfalfa would be converted to glucose and cause a blood sugar spike, just like feeding something that is too high in sugar or starch.  Nice theory but it doesn’t hold up to scrutiny.

Gluconeogenesis is the process of creating glucose from precursors such as lactate, pyruvate, other derivatives of some amino acids and other substances like propionate.  It occurs primarily in the liver, to a small extent in the kidney, and is a normal function.  This is how all animals maintain normal blood sugar levels when glucose is not being absorbed from the intestinal tract.

The fault with the theory that high protein or propionate preservatives in alfalfa cause a blood sugar spike from gluconeogenesis is quite simply that they don’t.  The carbon backbones of amino acids can themselves be directly burned for energy.  If they, or propionate, are converted to glucose that glucose is not necessarily released into the blood.  It can be stored as glycogen or fat if blood sugar is already normal.  This process is under the control of the hormone glucagon.

Drs. Rodiek and Stull published a study on the glycemic index of common feeds in 1988.  Glycemic index refers to how high blood sugar goes after eating.  Oats is assigned a value of 100 and other feeds described as a % of the blood glucose level seen after feeding oats. They studied blood glucose levels for 5 hours after feeding 10 different foods to horses, including alfalfa.  That study, and five others since, have clearly shown the blood sugar response to feeding alfalfa is extremely low.


As for propionate, a 1971 study by Drs. Argenzio and Hintz, two of the premier equine nutritionists in the last century, found that administering a load of propionate to ponies causes no rise in blood glucose in animals that had not been fasted.  When fasted before the propionate was given, there was a increase in glucose from lower than normal levels to a low normal glucose level (70 mg/dL to 83.8 mg/dL on average).  This is consistent with gluconeogenesis from the propionate but release of glucose regulated by glucagon to keep glucose well within the normal range – no spike.

So, while it remains true that alfalfa is problematic for some IR horses, the reason for this is still unknown.

Eleanor 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.
This entry was posted in Equine Nutrition and tagged , , , , , , . Bookmark the permalink.

4 Responses to Alfalfa and the IR Horse

  1. Joe Sibiski says:

    Dr. Kellon, thank you. Your blog could be the basis of an advanced degree in equine nutrition, at least for us amateurs with one horse. When I was introduced to your blog (through a Pete Ramey blog article), I read all your articles in one evening, then reread them the next night. I spot read every night for a week.

    After a couple of weeks “off,” well, here I am again. I have a specific question that popped up in my reading of this article. It relates to the glycemic index, and blood sugar issues.

    But it would be too presumptuous, and unfair, of me to ask. It’s just great to know that if I keep digging into what you uncover for us, I will find it.


    • uckeleequine says:

      Thank you very much for your kind comments. As for any questions, please do just ask. That’s what this space is for!


    • uckeleequine says:

      Thank you very much for your kind comments. As for any questions, please do just ask. That’s what this space is for!


      • Joe Sibiski says:

        Thank you for your willingness to consider my question. I must say I feel like a child who sings out of tune asking for instruction from a great opera singer. Here goes…

        We have a five-year-old half Arabian mare we purchased at auction two and a half years ago. I have been training her using the “clicker” system, with pieces of carrot as the food reward – up to a hundred pieces a session (400 grams plus or minus 30 grams). When I saw the glycemic index in your article, red flags started popping up in her feed bucket.

        My question is, am I endangering the health of our horse in any way?

        Here is the relevant information (I believe):

        She is 14h1″, probably around 800 pounds.

        She has free access to a round bale, which is within a slow-feed net. Soon she and her pen-mate will feed from several small slow-feed nets, strung out to promote their movement throughout the day. There is no point to assaying the hay, as new shipments of widely varying “ages” from at least two different sources arrive on a monthly basis.

        She is “barefoot,” though her farrier is suspect. It is I. I attempt to follow Pete Ramey’s system (especially the “less is more” part).

        She receives two supplemental feedings per day. In the morning it is one pint of Equilene Complete. Here are ingredients that are listed on the glycemic index in your article. The number represents placement on the list. 1. Dehydrated alfalfa meal. 2. Wheat middlings. 3. Rice hulls. 4. Rice bran.

        In the late afternoon she is fed a half pound of whole oats. (I would like to move to whole oats for both feedings, but am hesitant. I need more information, which I am finding on your blog.)

        Supplements that are mainly split between the two feedings: Vitamin E oil, 821.6 IU’s, 2 teaspoons iodized salt, 1 oz probiotic (for 24 days it was 2 oz), 2 oz ground flax, 2 ounces brewer’s yeast, 2 oz complete vitamin-mineral.

        Now the kicker – up to 400 grams of carrots per day (which I calculate has 19 grams of sugar).

        Can you offer any advice? I understand if it is to fire our nutritionist. Thanks! Joe


Leave a Reply

Fill in your details below or click an icon to log in: Logo

You are commenting using your account. Log Out /  Change )

Google photo

You are commenting using your Google account. Log Out /  Change )

Twitter picture

You are commenting using your Twitter account. Log Out /  Change )

Facebook photo

You are commenting using your Facebook account. Log Out /  Change )

Connecting to %s

This site uses Akismet to reduce spam. Learn how your comment data is processed.