Mineral supplementation is a requirement in the diets of all food animal species, including pigs. Trace minerals are included in mg/kg concentrations in the complete diet and although the concentration is low, a lack of these minerals can be detrimental to the growth and physiology of the animal. Manganese is a trace mineral supplemented to promote growth and reproductive efficiency in swine. Manganese plays a role in the structure and physiological function of the pig. Establishing optimal manganese requirements in pigs is of great importance to the swine industry as a whole, because existing literature is variable in its conclusions surrounding the subject. Iodine is another trace mineral that is known to be required, but an ideal dietary requirement promoting growth has yet to be determined. Iodine is a cofactor required for the synthesis of thyroid hormones, which promote the growth of the animal. The research presented in this dissertation will evaluate these mentioned trace minerals on various reproductive, growth, and physiological parameters in swine. In addition, there is preliminary evidence presented in this dissertation investigating the effects of manganese on the fecal microbial populations present in pigs. Data presented here can serve as a foundation for additional research surrounding the supplementation of these minerals to the diets of pigs and have a positive impact on the global swine industry.