Feeding the HYPP HorseBy Martin W. Adams, PhD, PAS - Equine Nutritionist for Southern States · April 19, 2017
Hyperkalemic Periodic Paralysis (HYPP) is an inherited genetic defect that affects muscle function in the horse. Symptoms of HYPP can vary widely among horses, from mild muscle tremors to death from cardiac arrest or respiratory failure. HYPP horses are sensitive to high levels of potassium in their diets, as well as sudden changes in potassium levels that can be brought on by stress or pregnancy and dehydration.
Salt and water are especially important for HYPP horses, since a lack of salt or water reduces urination, which is how the horse secretes potassium. Provide continuous access to a clean source of water and loose salt or a pure salt block (white) to a horse with HYPP. Keep in mind some mineral blocks and most electrolytes contain added potassium. Avoid providing mineral blocks and electrolytes with added potassium to an HYPP horse.
Horses that have been diagnosed or suspected of having HYPP should have low dietary potassium levels in their feed rations, less than 1.3% (as fed basis). A horse is more prone to an attack two to five hours after a meal, when potassium is at its peak in the bloodstream. Avoid training or working the horse, if possible, during this time.
It’s important to know hay can have a much higher potassium level than commercial horse feeds or feedstuffs like oats. Grass hay usually contains a lower potassium level than alfalfa hay, therefore only grass or mixed hay is recommended for HYPP horses. Feeding Legends® CarbCare™ Performance or Legends CarbCare Senior for mature horses, with a limited amount of hay, allows for more control over the potassium level of the total diet. If possible, break your horse’s feed ration into two to four meals per day, providing hay twice daily.