Every performance horse owner has a very rigorous exercise and feeding program. Today, there are so many dietary supplements that it is very easy to ensure your pet has all the nutrients it needs to function optimally. However, even with all these extra additives, every horse needs the basics in their diet. It is mainly roughage. For people who do not have access to pasture all year round, the alternative is hay. The first step in the hay production process is standing cultivation. Growing crops contain bacteria and yeast. This is where potential mold growth begins (Smith). Once the crop is cut, the moisture in the plant decreases very quickly. This now allows a new group of microbes to begin to reproduce and spread. Hay that is apparently dusty but has no visual evidence of mold is caused by fungi growing in cut hay drying in the field. Once the hay is baled, another new group of microbes (mostly fungi and yeast) begins to reproduce (Smith). These new mushrooms are better adapted to occupy this new, drier and warmer niche. The most common molds found in hay include Alternaria, Aspergillus, Cladosporum, Fusarium, Mucor, Penicillium and Rhizopus. Each of these types causes spores that can cause problems in livestock and especially horses (Lemus). Among these common types of mushrooms, there are three types that start growing mainly during storage; These are Aspergillis, Fusarium and Penicillium. Several of the fungi that grow during the hay bale storage process are known to produce mycotoxins. These are the organisms that feed on the organic sugars and acids released by the plant during the drying process and they are also the types of fungi that cause hay to become moldy (Smit...... middle of paper... .. w.mycotoxins.info/‌myco_info/‌animh_cs.html>.Kapper, Don. “Potentially Toxic Food Contaminants and Additives to Horses” AOCS.org, 2012. Web, February 16, 2012. .Mauger, Robyn and yours. horse.” Horsetalk, nd Web. “Mycelium-Webster Dictionary”, nd.. 2012..