By carb I am referring to hydrolyzable carbohydrate digested to glucose in the small intestine. This includes starch and the sugar/ESC (ethanol soluble carbohydrates) fractions on an analysis. These are the carbs that elevated glucose and cause an insulin response. Fiber and fructans are also carbohydrates but do not cause an insulin spike.
Low carb feeds are needed for horses with high insulin related to insulin resistance/metabolic syndrome or PPID (Cushing’s disease) as well as myopathies like EPSM/equine polysaccharide storage myopathy (aka PSSM) and recurrent exertional rhabdomyolysis (RER) – tying up. These feeds are also useful for easy keepers or weight loss as long as there is no added fat, for inactive or injured horses, horses that become too “high” on grains and for horses which develop soft manure when fed grains. Many of the commonly used high fiber ingredients are prebiotic since they are easily fermented and therefore support good populations of those bacteria.
If you think substituting plain grass hay pellets will always keep your bucket meals below 10% you’re wrong. Young growths of hay are best for pellets because they hold together easier but are also highest in sugar and starch. Beet pulp can be a good choice but may have molasses added or be too high in residual sugars. When using beet pulp, always rinse it well before and after soaking. This will remove extra molasses and sugars.
Before getting to ingredients, an important point here is how low is low enough. There is no shortage of feeds claiming to be low or safe, but many are anything but and they may be as high as 25% starch or sugar+starch combined – and that includes “balancers”. For horses with issues related to high insulin or myopathies, that number should be 10% or lower. If the manufacturer does not volunteer this data in their product information, contact them and ask to see a typical analysis.
You also want to know if the feed if fixed formula, aka locked formula, which means the ingredients and their relative percentages do not change. Do not buy anything where the ingredients list mentions “products” or “by-products”. Those generic terms can encompass many different ingredients. Take a look at the guarantee analysis. You want to see fiber over 20% and fat no higher than 3%. Ideally, there is no added iron in the formula since metabolic horses are commonly iron overloaded and the base diet already has plenty of iron. Check the ingredients list for items starting with iron or ferrous.
- Soybean hulls. These are the thin outer coating on the bean, like the skins on peanuts inside the shell. They are an excellent protein source (29% protein), ultra low sugar and starch, easily fermented fiber.
- Beet pulp. Again, very low sugar and starch, rich in easily fermented fiber. Also holds moisture well if you need to feed wet.
- Flaxseed. Rich in omega-3 fatty acids lacking in other diet ingredients, low sugar and starch, high levels of easily fermented soluble fiber.
- Distillers or Brewers dried grains. These are grains that have been fermented for ethanol production. They are high protein, low sugar and starch but high taste appeal.
- Grass hay or alfalfa meal. Alfalfa can be an issue for some metabolic horses but low levels in a multiingredient feed improve palatability.
- Wheat middlings. These are a mixture of the most nutritious parts of the grain (e.g. bran, germ) that would otherwise be wasted in the production of white flour. High protein contributes to the amino acid diversity of the feed. Greatly reduced starch.
It takes some time and investigation to find out the details on feeds but the effort is well worth it. A correctly formulated feed is both safe and appealing to the horse.
Eleanor Kellon, VMD