How to feed HYPP Horses: Potassium is key

The main dietary goal in managing an HYPP (Hyperkalemic Periodic Paralysis) horse is keeping total dietary potassium under 1.0%. It is key to look at the total dietary potassium instead of just the hay or just the grain source.

To figure out total dietary potassium (or any other nutrient level), use the following formula:

((Pounds of hay x percent potassium in hay) + (Pounds of grain x percent potassium in grain)) / Total pounds of feed.

For example, if you are feeding 15 lbs a day of a grass hay that measures 1.0% potassium, along with 6 lbs a day of a grain mix that measures 0.8% potassium, then your calculations would be as follows:

((15 x 0.01) + (6 x 0.008)) / 21 = 0.942% total dietary potassium.

Find out the potassium of your hay source, and of your grain, and then you can figure out your horse’s total dietary potassium level.

19 Replies to “How to feed HYPP Horses: Potassium is key”

  1. I feed Lite balance and Senior Nutrena feeds-the probelm is everyplace carries the Senior and Safe choice but only one place carries the Lite Balance and they don’t have convient at all hours. Why do the places that carry the other 2 not carry the Lite balance also–I know there are plenty of hefty horses out there!! Please don’t tell me it’s up to the stores –they say it’s up to their Nutrena Rep. what they carry. I’m in S.W. Wis. so Gassers in Boscobel or Farm and Fleet would help out !

    1. Hello Randi – Thanks for commenting, and we’re glad you like our products so much! We do allow any of our dealers to purchase from us any of our products. That said, chain stores such as Gassers or Farm & Fleet take a bit more to carry a product due to being a chain versus a single-location independent store. I’m going to have one of our local reps contact you via email to help get you situated, OK? Thanks again for contacting us! ~Gina T.

      1. I wanted to know which Nutrena feed to use for our HYPP horse? He is an aged guy, 22. Gets all of the grass hay he can eat. Unfortunately in our area stabling is our only option so he stalled but gets regular daily excersize. The owners we are leasing him from said they feed a complete feed (or senior), all the grass hay he can eat as well as a flake of alfalfa daily. We do have another horse who is strictly fed whole oats (Nutrena’s of course!) with a vitamin supplement…he is not HYPP and is a easy keeping Arabian. What I read says to use whole oats and few other feed stuffs. I’m a HUGE Nutrena fan and wish to use Nutrena feeds only. This guy has had very few eppisodes in his long life time and we wish to keep it that way!

    1. Great question. Sound you have two entirely different diets to maintain.
      With any HYPP horse the goal is to keep the potassium level below 1% in the TOTAL diet.

      1. Hay your grass hay tested to see what level it is currently. Alfalfa hay contains about 2.4% potassium.

      2.As for feeds straight oats are always a good feed with potassium ranges from 0.4 to 0.6% per pound. However, two products that Nutrena offers that would also work for your horse, and provide appropriate potassium levels are Vitality 10 and Vitality Ultra (if available in your market area) as they have potassium contents of about 0.8%.
      You stated this horse is a hard keeper, and I feel the Vitality feed would work well for him, providing good quality calories, as well as quarantined lysine and methionine levels, biotin, organic trace minerals, as yeast culture for enhanced protein digestion and absorption.

      For the easy keeper Arabian, I would suggest SafeChoice. With high fat, fiber and controlled starch you will minimize the risk of nutritionally related problems. The balance of vitamins, minerals, biotin, yeast culture provide a well balanced feed program for our easy keepers. The feed rate for easy keepers is .25 for every 100 pounds of body weight.

      You will need to determine your horses weight to calculate the proper feed amounts. Click here to see a blog post on how to weigh your horse.
      Ideally 1.5 – 2% of their body weight per day should be forage.

      We hope this helps you, and if you have any more questions, let us know! ~Gayle R.

  2. Good information that you offered here, I think I can derive what I might consider feeding my QH. I have not had her HYPP tested though am suspect. Will likely have her tested when next the vet is out. Let me get your advice: 11 y/o fleshy, easy keeper QH w/ all day turn-out, La. heat, lite summer work load (I can’t take the heat in the summer here!!), no hay, feeding 1/3 scoop mix of oats/10% grain twice daily. Over the winter I had weighed her feed but at that time she was getting 1/2 a scoop twice daily. So not sure the weight. Anyway, it amounts to about two, two handed scoops of feed. If it wasn’t for her herd mates coming in for dinner, I suspect she wouldn’t always bother with coming in for what little she is being fed.
    I would like to feed an oat/grain mix as oats are low in potassium and a good grain will assure I am meeting her nutritional needs. What are your thoughts?

    1. Hi Stephanie, Great question! We generally recommend feeding our Vitality Perform products to HYPP horses, due to the cereal grain (and thus lower potassium) content. If fed at the minimum recommended amount for her size – which would be approximately 3 lbs per day) then it would contribute about 0.024% potassium to her daily diet. You could also drop the straight oats from her feeding plan, as they are already in the Vitality, and adding more oats actually throws off the nutritional balance of the feed.

      And of course, don’t forget this doesn’t include the amount of potassium from pasture, which is the bulk of the diet and the main contributing factor to achieving that overall 0.1% or less potassium level in the diet. It is hard to know how much potassium your horse could be getting from pasture, but you could contact a local ag extension agent to get an idea or get soil sampling done. You also have to be careful of fertilizer application that is used on pasture for HYPP horses. If you feed hay in the winter time, you may want to consider having that tested.

      Hope that helps!

      Thanks ~ Gina T.

    1. Hello Sally, Thanks for checking in with us! There is not a lot of available information on Teff hay in regards to the potassium content – your best bet would be to have your local supply tested to know for sure. Most of the information available on this hay that was originally imported from Ethiopia revolves around the protein & sugar content, although there is some conflicting information even on those two nutrients. Many claim it to be high in protein and low in sugards, however Rutgers University has some conflicting information on the subject.
      Good luck! Gina T.

  3. Hello, I’m looking to consolidate my 3 different horses’ feeding regiment and feed all 3 something uniform. They’re moving to a new barn that is partially self-care; they’ll have 24/7 turnout available. The youngest is a 5 yr old QH, extremely easy keeper. The next oldest is 7, HYPP, not an easy keeper. And the oldest is a 21 yr old QHx, easy keeper. The younger 2 have been on oats, my senior has been on 10% sweet feed. Ideally I would like to find something all 3 can have that would meet their needs. All 3 are in steady work, with differing degrees of intensity.

    1. Hello Abigail, Thank you for your question about consolidating the feeding program for 3 different horses. It presents an interesting challenge with some different needs.

      The HYPP horse requires the first consideration as the goal is to keep the potassium content of the total diet below 1.0 or 1.1% to minimize risk of HYPP symptoms (assuming the horse is not on medication). The lowest potassium feeds are high grain content textured/sweet feeds with moderate molasses content. You would also want to find out what kind of hay they are using and perhaps have it analyzed to check potassium content. In Nutrena, our best choices for HYPP horses are Vitality Ultra and Vitality Perform 10 and 12.

      You should be able to feed this same feed to your other two horses as long as your senior horse has good dentition and is able to chew hay OK. At some point, you may have to switch the older horse to Senior. The time to switch will be when your horse starts to show typical signs of loss of muscle mass and tone along with perhaps some body condition loss.

      Best wishes,
      Roy J

    1. Hi Stacy,
      Would you be willing to share where you are located so we can provide availability of suggested product? Thanks!

    1. Hi Candy,
      In an effort to give you the best recommendation, we would love to here where you are located, what ProForce product you are looking at feeding, and what type of forage you are feeding. This will give us a better scope of what products are available to you and at what feeding rate.

    1. Hi Mary,
      Good question. Target intake per day is less than 1% dietary K (Potassium) in the total diet for a horse with HYPP. It is important to remember that total diet means all pasture, hay , feed, supplements and treats; therefore mg will vary basis total pounds of intake and thus we calculate as a percentage of total diet. So, for example if an 1100# horse is eating 25# total per day (20# hay and 5# feed) they could have up to 1% of that 25# as K per day which would equate to 122 grams (122,000 mg). To provide a per ingredient or feedstuff basis, I’ll use the same example; if the hay fed tests at .8% K and the feed tests at 1.3% K, the total diet would still only contain .9% K (102 grams or 102,000 mg) and be considered acceptable for a horse with HYPP. Forage is the largest source of potassium and thus should be tested at a forage lab prior to feeding as cuttings are highly variable.

      Best of luck!
      Abby K.

  4. I have a 19 yr old mare, dry lot turn out bermuda grass hay, free choice. She is HYPP and also allergic to anything with rice bran.

    She has been on Safe Choice Special Care but her coat and overall look has gone down.

    I was feeding oats/corn only. Prior to switching to Safe Choice
    On the website I can’t see any of the ingredients in the feed or any potassium levels.

    I see you have recommended Vitality products for Hypp horses. Do any contain rice bran? And what if my feed stores do not carry this? I ran into an issue trying to get ProForce XTN no feed dealer can get this product in Arizona…. ridiculous

    1. Hello Lisa, Thanks for the question. The ProForce line has recently been expanded to more of the US, so you might check with your local retailers again on that. That said, if your HYPP horse is N/H and has few or no episodes, she can successfully be managed on the SafeChoice Special Care (which does not contain rice bran), provided your hay is a low potassium hay. Check how much you are feeding against the recommended amount for her weight and activity level here:

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