Horses are creatures of habit and do not adapt to change very easily. A new sound, smell, person or routine can sometimes rattle them. And, a change in their ration will stress their system, sometimes with devastating consequences. It’s often easy to overlook just how drastic those ration changes can be.
When a horse is free to graze in the wild for 100 percent of his nutrients, dietary changes are usually induced by weather or predators. But, domestication of the horse has provided us with the power to control our animals’ rations at a whim. When we change rations for convenience according to their cost and availability, the true cost of that change might mean the horse’s life.
As we feed our horses we must remember we are also feeding the billions of bacteria and protozoa that live in their gastrointestinal systems. Collectively, these bacteria and protozoa are called intestinal microbes and a horse’s health is directly related to the health of those microbes.
Some of these microbes are good guys and some are not. Over time, a horse’s diet will select for various microbes. If large amounts of starch (grains) are fed, different microbes will thrive than those living on a fiber-based diet (hay and pasture). We know now that starch-based diets will select for particular microbes that increase the risk of colic and laminitis. The byproducts of these starch-based microbes will selectively favor colonization of their own kind.
The rule of thumb for changing grain rations is to do it slowly over a seven to ten-day period. Even so, microbiologists who study equine microbes have claimed that it can take up to 60 days for a horse’s intestinal microbes to adapt to a dietary change. This creates some real challenges with regard to the changing seasons, show schedules and convalescent horses.
Those of us who travel extensively with horses must be good planners to ensure dietary consistency. What do you do if you run out of grain while traveling and cannot find your brand? In a pinch, the safest ration to feed in this situation are plain oats. Oat starch is easily digestible and the grain is naturally high in fiber. The worst choice would be to top dress a horse’s ration with corn. There is nothing inherently wrong with limited corn in a fully balanced and acclimated ration. However, top dressing corn is a dangerous habit because cornstarch is the least digestible and radical additions of corn are stressful to microbe populations.
Sooner or later all of us will have to care for an injured horse that cannot be exercised. With less calories being burned, that horse requires less grain. In this case, feeding less grain and more fiber is much less stressful than the reverse scenario. While rapidly decreasing a horse’s grain ration when the horse doesn’t need it doesn’t pose much risk; when work is resumed, the increased grain portion should be given carefully and slowly.
Though feeding new hay is less stressful than feeding a new grain ration, even new hay will increase the risk of gastrointestinal problems. The use of hay or fiber supplements can lessen this risk. By feeding a few pounds a day of processed hay chops or cubes as the hay ration changes, horses will at least get a consistent portion of their fiber. Balanced beet pulp rations can also minimize the stress of hay changes. Shredded beet pulp is inherently low in starch and higher in digestible fibers. So, if you’re on the road and forced to use different hay or you change suppliers, less gastrointestinal stress will occur if you are already feeding hay cubes or a balanced beet pulp concentrate.
All of us have busy schedules and planning mistakes in nutrition can occur. Understanding the profound changes that can result in the gastrointestinal system and knowing a few methods to minimize these changes will lower the risk to a horse’s health and performance.