Question

I rescued a four-year-old Quarter Horse mare that tested positive for hyperkalemic periodic paralysis (HYPP). She needs to gain about 200 lb (90 kg) but requires a HYPP-preventive diet. How can I do that? Right now, she’s given whole oats twice a day and oat hay twice a day.

Answer

You are on the right track with your horse’s low-potassium diet, but it is not providing the necessary calories for weight gain or nutrients for optimal health. Ideally, the goal is to keep potassium intake between 0.6-1%. In order to achieve weight gain, her daily intake will need to increase.

Starting with forage, you may want to search for higher quality grass hay that will provide more calories and nutrients per pound. Timothy or bermudagrass hay might fit the bill. Avoid bromegrass and legumes such as alfalfa. I also recommend offering free-choice hay if you don’t already. You might be surprised at just how much hay she can eat in a day. It would not be out of the ordinary for her to eat 2.5-3% of her target body weight, for instance. Allowing her to eat as much hay as she wants mimics natural grazing patterns, so this will help with gastrointestinal health, too.

You didn’t mention the quantity of oats fed daily. Depending upon the current consumption, you may need to increase. Although oats are low in potassium, they are not fully fortified with the required nutrients for optimal health. For example, oats have an inverted calcium-to-phosphorus ratio that should be corrected with additional fortification. One way to balance the nutrients in this diet is by using a ration balancer pellet. These feeds are highly concentrated and designed to be fed at 1-2 lb (0.45-0.9 kg) per day. Because a ration balancer pellet is considered a low-intake feed, you can split the small amount into several meals to maintain low potassium. Since she has not exhibited signs you should be safe splitting the ration balancer into two meals.

Another feeding option that would increase calorie density is the addition of high-fat concentrate. If you abide by the rule of no more than 30 g of potassium per meal, you could still feed up to 6 lb (2.7 kg) of feed without reaching that limit with a 1.05% potassium feed. KER generally recommends that grain meals should be 5 lb (2.3 kg) or less. Feeding a high-fat concentrate at the recommended feeding levels would negate the need for a ration balancer pellet.

It is also important to address any digestive tract problems that may be prohibiting weight gain. As a rescue horse put through stressful situations, she may have gastric ulcers or hindgut acidosis. By adding a daily preventative supplement like RiteTrac you can protect her entire digestive tract. RiteTrac contains the antacids and coating agents that work in the stomach along with a hindgut buffer. The hindgut buffer balances the pH to create a healthy environment for microbial populations and fermentation. RiteTrac is available in the U.S. and other markets. Australian horse owners should look for research-proven products.