Lately, we have seen commercials that promote striking the balance of "good bugs" in our own gastrointestinal (GI) tracts. Our local grocery likely has a variety of colorfully packaged yogurts boasting "live and active cultures." These products are designed to keep the good microflora happy and reduce the amount of detrimental bugs in our guts, but the jury is largely still out on their efficacy. Similarly, horses' GI tracts also need to reach this balance, but since these animals have a unique digestive system that enables them to process and utilize forages, different types of bugs are required.

Microbes in the hindgut (the large intestine and cecum) of the horse break down and ferment fibrous portions of roughages, producing volatile fatty acids that serve as a significant energy source. These microbes also create B vitamins and other nutrients essential to the health and well-being of the animal, and they help reduce the risk of overgrowth of potentially harmful bacteria such as Salmonella and Clostridium difficile. The microbial population (which includes bacteria, protozoa, yeasts, and fungi) of the hindgut must be healthy, and its numbers must be at appropriate levels for proper digestion. Bacteria make up the largest group, but the other good bugs play an important role.

When the levels of the good bugs wane–as in cases of stress, travel, or antibiotic administration–there are ways to replenish them with the help of probiotics and prebiotics. And while not available in your supermarket aisle, these equine products are readily available elsewhere. It's important to note there is limited scientific evidence in peer-reviewed journals on probiotics and prebiotics, so ask your veterinarian to advise you on the use of these products and where to find them