Hyperkalemic Periodic Paralysis and Colic

Q. I have a 4-year-old Quarter Horse gelding who is HYPP N/H positive. This horse is very gassy and tends to colic once a month, which causes a minor HYPP attack. I have tried everything, from changing his diet (no grain) to just oats, beet pulp, and grass, to giving him Prozyme and other products that have not worked. I think he seems a little anxious (worried) most of the time, and that may be causing his symptoms. What do you think about giving him an herbal supplement (chamomile) or some other form of a calmer? Are these safe for our horses to use on a daily regime? I feel that if I can stop his flatulence, I can prevent his colic HYPP attacks.


A. Feeding strategies to manage HYPP rely on feeds that contain no more than 1% potassium. Oats, barley, and corn contain less than 1% potassium. Water-soaked beet pulp can be combined half-and-half with grass hay to meet normal roughage needs while minimizing potassium intake. It is best to have grass hay analyzed, as some hays might have as high as 2.5% potassium content. Alfalfa hay, rich spring pasture, molasses, and sweet feed should be avoided, as should supplementation with potassium-containing electrolytes. Also, check labels on other feed and vitamin supplements to ensure minimum potassium content.

Attempting to use herbal supplements to ease your horse's anxiety might be an adjunctive solution, but it should not be your first course of action. Anxiety can occur for many reasons, not the least of which is feeling unwell. Use of any herbal supplement would mostly serve to put a Band-aid on a gaping wound. First, assess your horse's living arrangement and his relative ease with his equine companions to ensure that he is living in the most contented situation. It would be prudent to track down the source of your horse's colic since this stress tends to precipitate HYPP episodes.

Dietary modifications are helpful to limit gas-type colics, but in addition, there might be health issues that reduce normal intestinal function such that your horse tends to become overly gassy. Colic might be related to chronic gastric ulcers, intestinal parasite migration, sand ingestion, intestinal adhesions, or a variety of other causes. Abdominal radiography and ultrasound can help identify sand accumulation. Treatment with psyllium helps move sand through the intestines and serves as a source of probiotics when it is metabolized by bacteria in the hindgut. Implementing a feeding arrangement that removes hay from the ground is critical to managing sand ingestion.

Gastric endoscopy is useful to identify stomach ulcers, and therapy with omeprazole and/or ranitidine can help these heal. Discuss with your veterinarian a comprehensive parasite control program to minimize this as a source of colic.

About the Author

Nancy S. Loving, DVM

Nancy S. Loving, DVM, owns Loving Equine Clinic in Boulder, Colorado, and has a special interest in managing the care of sport horses. Her book, All Horse Systems Go, is a comprehensive veterinary care and conditioning resource in full color that covers all facets of horse care. She has also authored the books Go the Distance as a resource for endurance horse owners, Conformation and Performance, and First Aid for Horse and Rider in addition to many veterinary articles for both horse owner and professional audiences.

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